| /* |
| * Functions related to setting various queue properties from drivers |
| */ |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/bio.h> |
| #include <linux/blkdev.h> |
| #include <linux/bootmem.h> /* for max_pfn/max_low_pfn */ |
| #include <linux/gcd.h> |
| #include <linux/lcm.h> |
| #include <linux/jiffies.h> |
| #include <linux/gfp.h> |
| |
| #include "blk.h" |
| |
| unsigned long blk_max_low_pfn; |
| EXPORT_SYMBOL(blk_max_low_pfn); |
| |
| unsigned long blk_max_pfn; |
| |
| /** |
| * blk_queue_prep_rq - set a prepare_request function for queue |
| * @q: queue |
| * @pfn: prepare_request function |
| * |
| * It's possible for a queue to register a prepare_request callback which |
| * is invoked before the request is handed to the request_fn. The goal of |
| * the function is to prepare a request for I/O, it can be used to build a |
| * cdb from the request data for instance. |
| * |
| */ |
| void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn) |
| { |
| q->prep_rq_fn = pfn; |
| } |
| EXPORT_SYMBOL(blk_queue_prep_rq); |
| |
| /** |
| * blk_queue_unprep_rq - set an unprepare_request function for queue |
| * @q: queue |
| * @ufn: unprepare_request function |
| * |
| * It's possible for a queue to register an unprepare_request callback |
| * which is invoked before the request is finally completed. The goal |
| * of the function is to deallocate any data that was allocated in the |
| * prepare_request callback. |
| * |
| */ |
| void blk_queue_unprep_rq(struct request_queue *q, unprep_rq_fn *ufn) |
| { |
| q->unprep_rq_fn = ufn; |
| } |
| EXPORT_SYMBOL(blk_queue_unprep_rq); |
| |
| /** |
| * blk_queue_merge_bvec - set a merge_bvec function for queue |
| * @q: queue |
| * @mbfn: merge_bvec_fn |
| * |
| * Usually queues have static limitations on the max sectors or segments that |
| * we can put in a request. Stacking drivers may have some settings that |
| * are dynamic, and thus we have to query the queue whether it is ok to |
| * add a new bio_vec to a bio at a given offset or not. If the block device |
| * has such limitations, it needs to register a merge_bvec_fn to control |
| * the size of bio's sent to it. Note that a block device *must* allow a |
| * single page to be added to an empty bio. The block device driver may want |
| * to use the bio_split() function to deal with these bio's. By default |
| * no merge_bvec_fn is defined for a queue, and only the fixed limits are |
| * honored. |
| */ |
| void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn) |
| { |
| q->merge_bvec_fn = mbfn; |
| } |
| EXPORT_SYMBOL(blk_queue_merge_bvec); |
| |
| void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn) |
| { |
| q->softirq_done_fn = fn; |
| } |
| EXPORT_SYMBOL(blk_queue_softirq_done); |
| |
| void blk_queue_rq_timeout(struct request_queue *q, unsigned int timeout) |
| { |
| q->rq_timeout = timeout; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_rq_timeout); |
| |
| void blk_queue_rq_timed_out(struct request_queue *q, rq_timed_out_fn *fn) |
| { |
| q->rq_timed_out_fn = fn; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_rq_timed_out); |
| |
| void blk_queue_lld_busy(struct request_queue *q, lld_busy_fn *fn) |
| { |
| q->lld_busy_fn = fn; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_lld_busy); |
| |
| /** |
| * blk_set_default_limits - reset limits to default values |
| * @lim: the queue_limits structure to reset |
| * |
| * Description: |
| * Returns a queue_limit struct to its default state. |
| */ |
| void blk_set_default_limits(struct queue_limits *lim) |
| { |
| lim->max_segments = BLK_MAX_SEGMENTS; |
| lim->max_integrity_segments = 0; |
| lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK; |
| lim->max_segment_size = BLK_MAX_SEGMENT_SIZE; |
| lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS; |
| lim->max_write_same_sectors = 0; |
| lim->max_discard_sectors = 0; |
| lim->discard_granularity = 0; |
| lim->discard_alignment = 0; |
| lim->discard_misaligned = 0; |
| lim->discard_zeroes_data = 0; |
| lim->logical_block_size = lim->physical_block_size = lim->io_min = 512; |
| lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT); |
| lim->alignment_offset = 0; |
| lim->io_opt = 0; |
| lim->misaligned = 0; |
| lim->cluster = 1; |
| } |
| EXPORT_SYMBOL(blk_set_default_limits); |
| |
| /** |
| * blk_set_stacking_limits - set default limits for stacking devices |
| * @lim: the queue_limits structure to reset |
| * |
| * Description: |
| * Returns a queue_limit struct to its default state. Should be used |
| * by stacking drivers like DM that have no internal limits. |
| */ |
| void blk_set_stacking_limits(struct queue_limits *lim) |
| { |
| blk_set_default_limits(lim); |
| |
| /* Inherit limits from component devices */ |
| lim->discard_zeroes_data = 1; |
| lim->max_segments = USHRT_MAX; |
| lim->max_hw_sectors = UINT_MAX; |
| lim->max_sectors = UINT_MAX; |
| lim->max_write_same_sectors = UINT_MAX; |
| } |
| EXPORT_SYMBOL(blk_set_stacking_limits); |
| |
| /** |
| * blk_queue_make_request - define an alternate make_request function for a device |
| * @q: the request queue for the device to be affected |
| * @mfn: the alternate make_request function |
| * |
| * Description: |
| * The normal way for &struct bios to be passed to a device |
| * driver is for them to be collected into requests on a request |
| * queue, and then to allow the device driver to select requests |
| * off that queue when it is ready. This works well for many block |
| * devices. However some block devices (typically virtual devices |
| * such as md or lvm) do not benefit from the processing on the |
| * request queue, and are served best by having the requests passed |
| * directly to them. This can be achieved by providing a function |
| * to blk_queue_make_request(). |
| * |
| * Caveat: |
| * The driver that does this *must* be able to deal appropriately |
| * with buffers in "highmemory". This can be accomplished by either calling |
| * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling |
| * blk_queue_bounce() to create a buffer in normal memory. |
| **/ |
| void blk_queue_make_request(struct request_queue *q, make_request_fn *mfn) |
| { |
| /* |
| * set defaults |
| */ |
| q->nr_requests = BLKDEV_MAX_RQ; |
| |
| q->make_request_fn = mfn; |
| blk_queue_dma_alignment(q, 511); |
| blk_queue_congestion_threshold(q); |
| q->nr_batching = BLK_BATCH_REQ; |
| |
| blk_set_default_limits(&q->limits); |
| |
| /* |
| * by default assume old behaviour and bounce for any highmem page |
| */ |
| blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH); |
| } |
| EXPORT_SYMBOL(blk_queue_make_request); |
| |
| /** |
| * blk_queue_bounce_limit - set bounce buffer limit for queue |
| * @q: the request queue for the device |
| * @dma_mask: the maximum address the device can handle |
| * |
| * Description: |
| * Different hardware can have different requirements as to what pages |
| * it can do I/O directly to. A low level driver can call |
| * blk_queue_bounce_limit to have lower memory pages allocated as bounce |
| * buffers for doing I/O to pages residing above @dma_mask. |
| **/ |
| void blk_queue_bounce_limit(struct request_queue *q, u64 dma_mask) |
| { |
| unsigned long b_pfn = dma_mask >> PAGE_SHIFT; |
| int dma = 0; |
| |
| q->bounce_gfp = GFP_NOIO; |
| #if BITS_PER_LONG == 64 |
| /* |
| * Assume anything <= 4GB can be handled by IOMMU. Actually |
| * some IOMMUs can handle everything, but I don't know of a |
| * way to test this here. |
| */ |
| if (b_pfn < (min_t(u64, 0xffffffffUL, BLK_BOUNCE_HIGH) >> PAGE_SHIFT)) |
| dma = 1; |
| q->limits.bounce_pfn = max(max_low_pfn, b_pfn); |
| #else |
| if (b_pfn < blk_max_low_pfn) |
| dma = 1; |
| q->limits.bounce_pfn = b_pfn; |
| #endif |
| if (dma) { |
| init_emergency_isa_pool(); |
| q->bounce_gfp = GFP_NOIO | GFP_DMA; |
| q->limits.bounce_pfn = b_pfn; |
| } |
| } |
| EXPORT_SYMBOL(blk_queue_bounce_limit); |
| |
| /** |
| * blk_limits_max_hw_sectors - set hard and soft limit of max sectors for request |
| * @limits: the queue limits |
| * @max_hw_sectors: max hardware sectors in the usual 512b unit |
| * |
| * Description: |
| * Enables a low level driver to set a hard upper limit, |
| * max_hw_sectors, on the size of requests. max_hw_sectors is set by |
| * the device driver based upon the combined capabilities of I/O |
| * controller and storage device. |
| * |
| * max_sectors is a soft limit imposed by the block layer for |
| * filesystem type requests. This value can be overridden on a |
| * per-device basis in /sys/block/<device>/queue/max_sectors_kb. |
| * The soft limit can not exceed max_hw_sectors. |
| **/ |
| void blk_limits_max_hw_sectors(struct queue_limits *limits, unsigned int max_hw_sectors) |
| { |
| if ((max_hw_sectors << 9) < PAGE_CACHE_SIZE) { |
| max_hw_sectors = 1 << (PAGE_CACHE_SHIFT - 9); |
| printk(KERN_INFO "%s: set to minimum %d\n", |
| __func__, max_hw_sectors); |
| } |
| |
| limits->max_hw_sectors = max_hw_sectors; |
| limits->max_sectors = min_t(unsigned int, max_hw_sectors, |
| BLK_DEF_MAX_SECTORS); |
| } |
| EXPORT_SYMBOL(blk_limits_max_hw_sectors); |
| |
| /** |
| * blk_queue_max_hw_sectors - set max sectors for a request for this queue |
| * @q: the request queue for the device |
| * @max_hw_sectors: max hardware sectors in the usual 512b unit |
| * |
| * Description: |
| * See description for blk_limits_max_hw_sectors(). |
| **/ |
| void blk_queue_max_hw_sectors(struct request_queue *q, unsigned int max_hw_sectors) |
| { |
| blk_limits_max_hw_sectors(&q->limits, max_hw_sectors); |
| } |
| EXPORT_SYMBOL(blk_queue_max_hw_sectors); |
| |
| /** |
| * blk_queue_max_discard_sectors - set max sectors for a single discard |
| * @q: the request queue for the device |
| * @max_discard_sectors: maximum number of sectors to discard |
| **/ |
| void blk_queue_max_discard_sectors(struct request_queue *q, |
| unsigned int max_discard_sectors) |
| { |
| q->limits.max_discard_sectors = max_discard_sectors; |
| } |
| EXPORT_SYMBOL(blk_queue_max_discard_sectors); |
| |
| /** |
| * blk_queue_max_write_same_sectors - set max sectors for a single write same |
| * @q: the request queue for the device |
| * @max_write_same_sectors: maximum number of sectors to write per command |
| **/ |
| void blk_queue_max_write_same_sectors(struct request_queue *q, |
| unsigned int max_write_same_sectors) |
| { |
| q->limits.max_write_same_sectors = max_write_same_sectors; |
| } |
| EXPORT_SYMBOL(blk_queue_max_write_same_sectors); |
| |
| /** |
| * blk_queue_max_segments - set max hw segments for a request for this queue |
| * @q: the request queue for the device |
| * @max_segments: max number of segments |
| * |
| * Description: |
| * Enables a low level driver to set an upper limit on the number of |
| * hw data segments in a request. |
| **/ |
| void blk_queue_max_segments(struct request_queue *q, unsigned short max_segments) |
| { |
| if (!max_segments) { |
| max_segments = 1; |
| printk(KERN_INFO "%s: set to minimum %d\n", |
| __func__, max_segments); |
| } |
| |
| q->limits.max_segments = max_segments; |
| } |
| EXPORT_SYMBOL(blk_queue_max_segments); |
| |
| /** |
| * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg |
| * @q: the request queue for the device |
| * @max_size: max size of segment in bytes |
| * |
| * Description: |
| * Enables a low level driver to set an upper limit on the size of a |
| * coalesced segment |
| **/ |
| void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size) |
| { |
| if (max_size < PAGE_CACHE_SIZE) { |
| max_size = PAGE_CACHE_SIZE; |
| printk(KERN_INFO "%s: set to minimum %d\n", |
| __func__, max_size); |
| } |
| |
| q->limits.max_segment_size = max_size; |
| } |
| EXPORT_SYMBOL(blk_queue_max_segment_size); |
| |
| /** |
| * blk_queue_logical_block_size - set logical block size for the queue |
| * @q: the request queue for the device |
| * @size: the logical block size, in bytes |
| * |
| * Description: |
| * This should be set to the lowest possible block size that the |
| * storage device can address. The default of 512 covers most |
| * hardware. |
| **/ |
| void blk_queue_logical_block_size(struct request_queue *q, unsigned short size) |
| { |
| q->limits.logical_block_size = size; |
| |
| if (q->limits.physical_block_size < size) |
| q->limits.physical_block_size = size; |
| |
| if (q->limits.io_min < q->limits.physical_block_size) |
| q->limits.io_min = q->limits.physical_block_size; |
| } |
| EXPORT_SYMBOL(blk_queue_logical_block_size); |
| |
| void blk_queue_erase_size(struct request_queue *q, unsigned int size) |
| { |
| q->limits.erase_size = size; |
| } |
| EXPORT_SYMBOL(blk_queue_erase_size); |
| |
| /** |
| * blk_queue_physical_block_size - set physical block size for the queue |
| * @q: the request queue for the device |
| * @size: the physical block size, in bytes |
| * |
| * Description: |
| * This should be set to the lowest possible sector size that the |
| * hardware can operate on without reverting to read-modify-write |
| * operations. |
| */ |
| void blk_queue_physical_block_size(struct request_queue *q, unsigned int size) |
| { |
| q->limits.physical_block_size = size; |
| |
| if (q->limits.physical_block_size < q->limits.logical_block_size) |
| q->limits.physical_block_size = q->limits.logical_block_size; |
| |
| if (q->limits.io_min < q->limits.physical_block_size) |
| q->limits.io_min = q->limits.physical_block_size; |
| } |
| EXPORT_SYMBOL(blk_queue_physical_block_size); |
| |
| /** |
| * blk_queue_alignment_offset - set physical block alignment offset |
| * @q: the request queue for the device |
| * @offset: alignment offset in bytes |
| * |
| * Description: |
| * Some devices are naturally misaligned to compensate for things like |
| * the legacy DOS partition table 63-sector offset. Low-level drivers |
| * should call this function for devices whose first sector is not |
| * naturally aligned. |
| */ |
| void blk_queue_alignment_offset(struct request_queue *q, unsigned int offset) |
| { |
| q->limits.alignment_offset = |
| offset & (q->limits.physical_block_size - 1); |
| q->limits.misaligned = 0; |
| } |
| EXPORT_SYMBOL(blk_queue_alignment_offset); |
| |
| /** |
| * blk_limits_io_min - set minimum request size for a device |
| * @limits: the queue limits |
| * @min: smallest I/O size in bytes |
| * |
| * Description: |
| * Some devices have an internal block size bigger than the reported |
| * hardware sector size. This function can be used to signal the |
| * smallest I/O the device can perform without incurring a performance |
| * penalty. |
| */ |
| void blk_limits_io_min(struct queue_limits *limits, unsigned int min) |
| { |
| limits->io_min = min; |
| |
| if (limits->io_min < limits->logical_block_size) |
| limits->io_min = limits->logical_block_size; |
| |
| if (limits->io_min < limits->physical_block_size) |
| limits->io_min = limits->physical_block_size; |
| } |
| EXPORT_SYMBOL(blk_limits_io_min); |
| |
| /** |
| * blk_queue_io_min - set minimum request size for the queue |
| * @q: the request queue for the device |
| * @min: smallest I/O size in bytes |
| * |
| * Description: |
| * Storage devices may report a granularity or preferred minimum I/O |
| * size which is the smallest request the device can perform without |
| * incurring a performance penalty. For disk drives this is often the |
| * physical block size. For RAID arrays it is often the stripe chunk |
| * size. A properly aligned multiple of minimum_io_size is the |
| * preferred request size for workloads where a high number of I/O |
| * operations is desired. |
| */ |
| void blk_queue_io_min(struct request_queue *q, unsigned int min) |
| { |
| blk_limits_io_min(&q->limits, min); |
| } |
| EXPORT_SYMBOL(blk_queue_io_min); |
| |
| /** |
| * blk_limits_io_opt - set optimal request size for a device |
| * @limits: the queue limits |
| * @opt: smallest I/O size in bytes |
| * |
| * Description: |
| * Storage devices may report an optimal I/O size, which is the |
| * device's preferred unit for sustained I/O. This is rarely reported |
| * for disk drives. For RAID arrays it is usually the stripe width or |
| * the internal track size. A properly aligned multiple of |
| * optimal_io_size is the preferred request size for workloads where |
| * sustained throughput is desired. |
| */ |
| void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt) |
| { |
| limits->io_opt = opt; |
| } |
| EXPORT_SYMBOL(blk_limits_io_opt); |
| |
| /** |
| * blk_queue_io_opt - set optimal request size for the queue |
| * @q: the request queue for the device |
| * @opt: optimal request size in bytes |
| * |
| * Description: |
| * Storage devices may report an optimal I/O size, which is the |
| * device's preferred unit for sustained I/O. This is rarely reported |
| * for disk drives. For RAID arrays it is usually the stripe width or |
| * the internal track size. A properly aligned multiple of |
| * optimal_io_size is the preferred request size for workloads where |
| * sustained throughput is desired. |
| */ |
| void blk_queue_io_opt(struct request_queue *q, unsigned int opt) |
| { |
| blk_limits_io_opt(&q->limits, opt); |
| } |
| EXPORT_SYMBOL(blk_queue_io_opt); |
| |
| /** |
| * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers |
| * @t: the stacking driver (top) |
| * @b: the underlying device (bottom) |
| **/ |
| void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b) |
| { |
| blk_stack_limits(&t->limits, &b->limits, 0); |
| } |
| EXPORT_SYMBOL(blk_queue_stack_limits); |
| |
| /** |
| * blk_stack_limits - adjust queue_limits for stacked devices |
| * @t: the stacking driver limits (top device) |
| * @b: the underlying queue limits (bottom, component device) |
| * @start: first data sector within component device |
| * |
| * Description: |
| * This function is used by stacking drivers like MD and DM to ensure |
| * that all component devices have compatible block sizes and |
| * alignments. The stacking driver must provide a queue_limits |
| * struct (top) and then iteratively call the stacking function for |
| * all component (bottom) devices. The stacking function will |
| * attempt to combine the values and ensure proper alignment. |
| * |
| * Returns 0 if the top and bottom queue_limits are compatible. The |
| * top device's block sizes and alignment offsets may be adjusted to |
| * ensure alignment with the bottom device. If no compatible sizes |
| * and alignments exist, -1 is returned and the resulting top |
| * queue_limits will have the misaligned flag set to indicate that |
| * the alignment_offset is undefined. |
| */ |
| int blk_stack_limits(struct queue_limits *t, struct queue_limits *b, |
| sector_t start) |
| { |
| unsigned int top, bottom, alignment, ret = 0; |
| |
| t->max_sectors = min_not_zero(t->max_sectors, b->max_sectors); |
| t->max_hw_sectors = min_not_zero(t->max_hw_sectors, b->max_hw_sectors); |
| t->max_write_same_sectors = min(t->max_write_same_sectors, |
| b->max_write_same_sectors); |
| t->bounce_pfn = min_not_zero(t->bounce_pfn, b->bounce_pfn); |
| |
| t->seg_boundary_mask = min_not_zero(t->seg_boundary_mask, |
| b->seg_boundary_mask); |
| |
| t->max_segments = min_not_zero(t->max_segments, b->max_segments); |
| t->max_integrity_segments = min_not_zero(t->max_integrity_segments, |
| b->max_integrity_segments); |
| |
| t->max_segment_size = min_not_zero(t->max_segment_size, |
| b->max_segment_size); |
| |
| t->misaligned |= b->misaligned; |
| |
| alignment = queue_limit_alignment_offset(b, start); |
| |
| /* Bottom device has different alignment. Check that it is |
| * compatible with the current top alignment. |
| */ |
| if (t->alignment_offset != alignment) { |
| |
| top = max(t->physical_block_size, t->io_min) |
| + t->alignment_offset; |
| bottom = max(b->physical_block_size, b->io_min) + alignment; |
| |
| /* Verify that top and bottom intervals line up */ |
| if (max(top, bottom) & (min(top, bottom) - 1)) { |
| t->misaligned = 1; |
| ret = -1; |
| } |
| } |
| |
| t->logical_block_size = max(t->logical_block_size, |
| b->logical_block_size); |
| |
| t->physical_block_size = max(t->physical_block_size, |
| b->physical_block_size); |
| |
| t->io_min = max(t->io_min, b->io_min); |
| t->io_opt = lcm(t->io_opt, b->io_opt); |
| |
| t->cluster &= b->cluster; |
| t->discard_zeroes_data &= b->discard_zeroes_data; |
| |
| /* Physical block size a multiple of the logical block size? */ |
| if (t->physical_block_size & (t->logical_block_size - 1)) { |
| t->physical_block_size = t->logical_block_size; |
| t->misaligned = 1; |
| ret = -1; |
| } |
| |
| /* Minimum I/O a multiple of the physical block size? */ |
| if (t->io_min & (t->physical_block_size - 1)) { |
| t->io_min = t->physical_block_size; |
| t->misaligned = 1; |
| ret = -1; |
| } |
| |
| /* Optimal I/O a multiple of the physical block size? */ |
| if (t->io_opt & (t->physical_block_size - 1)) { |
| t->io_opt = 0; |
| t->misaligned = 1; |
| ret = -1; |
| } |
| |
| /* Find lowest common alignment_offset */ |
| t->alignment_offset = lcm(t->alignment_offset, alignment) |
| & (max(t->physical_block_size, t->io_min) - 1); |
| |
| /* Verify that new alignment_offset is on a logical block boundary */ |
| if (t->alignment_offset & (t->logical_block_size - 1)) { |
| t->misaligned = 1; |
| ret = -1; |
| } |
| |
| /* Discard alignment and granularity */ |
| if (b->discard_granularity) { |
| alignment = queue_limit_discard_alignment(b, start); |
| |
| if (t->discard_granularity != 0 && |
| t->discard_alignment != alignment) { |
| top = t->discard_granularity + t->discard_alignment; |
| bottom = b->discard_granularity + alignment; |
| |
| /* Verify that top and bottom intervals line up */ |
| if ((max(top, bottom) % min(top, bottom)) != 0) |
| t->discard_misaligned = 1; |
| } |
| |
| t->max_discard_sectors = min_not_zero(t->max_discard_sectors, |
| b->max_discard_sectors); |
| t->discard_granularity = max(t->discard_granularity, |
| b->discard_granularity); |
| t->discard_alignment = lcm(t->discard_alignment, alignment) % |
| t->discard_granularity; |
| } |
| |
| return ret; |
| } |
| EXPORT_SYMBOL(blk_stack_limits); |
| |
| /** |
| * bdev_stack_limits - adjust queue limits for stacked drivers |
| * @t: the stacking driver limits (top device) |
| * @bdev: the component block_device (bottom) |
| * @start: first data sector within component device |
| * |
| * Description: |
| * Merges queue limits for a top device and a block_device. Returns |
| * 0 if alignment didn't change. Returns -1 if adding the bottom |
| * device caused misalignment. |
| */ |
| int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev, |
| sector_t start) |
| { |
| struct request_queue *bq = bdev_get_queue(bdev); |
| |
| start += get_start_sect(bdev); |
| |
| return blk_stack_limits(t, &bq->limits, start); |
| } |
| EXPORT_SYMBOL(bdev_stack_limits); |
| |
| /** |
| * disk_stack_limits - adjust queue limits for stacked drivers |
| * @disk: MD/DM gendisk (top) |
| * @bdev: the underlying block device (bottom) |
| * @offset: offset to beginning of data within component device |
| * |
| * Description: |
| * Merges the limits for a top level gendisk and a bottom level |
| * block_device. |
| */ |
| void disk_stack_limits(struct gendisk *disk, struct block_device *bdev, |
| sector_t offset) |
| { |
| struct request_queue *t = disk->queue; |
| |
| if (bdev_stack_limits(&t->limits, bdev, offset >> 9) < 0) { |
| char top[BDEVNAME_SIZE], bottom[BDEVNAME_SIZE]; |
| |
| disk_name(disk, 0, top); |
| bdevname(bdev, bottom); |
| |
| printk(KERN_NOTICE "%s: Warning: Device %s is misaligned\n", |
| top, bottom); |
| } |
| } |
| EXPORT_SYMBOL(disk_stack_limits); |
| |
| /** |
| * blk_queue_dma_pad - set pad mask |
| * @q: the request queue for the device |
| * @mask: pad mask |
| * |
| * Set dma pad mask. |
| * |
| * Appending pad buffer to a request modifies the last entry of a |
| * scatter list such that it includes the pad buffer. |
| **/ |
| void blk_queue_dma_pad(struct request_queue *q, unsigned int mask) |
| { |
| q->dma_pad_mask = mask; |
| } |
| EXPORT_SYMBOL(blk_queue_dma_pad); |
| |
| /** |
| * blk_queue_update_dma_pad - update pad mask |
| * @q: the request queue for the device |
| * @mask: pad mask |
| * |
| * Update dma pad mask. |
| * |
| * Appending pad buffer to a request modifies the last entry of a |
| * scatter list such that it includes the pad buffer. |
| **/ |
| void blk_queue_update_dma_pad(struct request_queue *q, unsigned int mask) |
| { |
| if (mask > q->dma_pad_mask) |
| q->dma_pad_mask = mask; |
| } |
| EXPORT_SYMBOL(blk_queue_update_dma_pad); |
| |
| /** |
| * blk_queue_dma_drain - Set up a drain buffer for excess dma. |
| * @q: the request queue for the device |
| * @dma_drain_needed: fn which returns non-zero if drain is necessary |
| * @buf: physically contiguous buffer |
| * @size: size of the buffer in bytes |
| * |
| * Some devices have excess DMA problems and can't simply discard (or |
| * zero fill) the unwanted piece of the transfer. They have to have a |
| * real area of memory to transfer it into. The use case for this is |
| * ATAPI devices in DMA mode. If the packet command causes a transfer |
| * bigger than the transfer size some HBAs will lock up if there |
| * aren't DMA elements to contain the excess transfer. What this API |
| * does is adjust the queue so that the buf is always appended |
| * silently to the scatterlist. |
| * |
| * Note: This routine adjusts max_hw_segments to make room for appending |
| * the drain buffer. If you call blk_queue_max_segments() after calling |
| * this routine, you must set the limit to one fewer than your device |
| * can support otherwise there won't be room for the drain buffer. |
| */ |
| int blk_queue_dma_drain(struct request_queue *q, |
| dma_drain_needed_fn *dma_drain_needed, |
| void *buf, unsigned int size) |
| { |
| if (queue_max_segments(q) < 2) |
| return -EINVAL; |
| /* make room for appending the drain */ |
| blk_queue_max_segments(q, queue_max_segments(q) - 1); |
| q->dma_drain_needed = dma_drain_needed; |
| q->dma_drain_buffer = buf; |
| q->dma_drain_size = size; |
| |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_dma_drain); |
| |
| /** |
| * blk_queue_segment_boundary - set boundary rules for segment merging |
| * @q: the request queue for the device |
| * @mask: the memory boundary mask |
| **/ |
| void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask) |
| { |
| if (mask < PAGE_CACHE_SIZE - 1) { |
| mask = PAGE_CACHE_SIZE - 1; |
| printk(KERN_INFO "%s: set to minimum %lx\n", |
| __func__, mask); |
| } |
| |
| q->limits.seg_boundary_mask = mask; |
| } |
| EXPORT_SYMBOL(blk_queue_segment_boundary); |
| |
| /** |
| * blk_queue_dma_alignment - set dma length and memory alignment |
| * @q: the request queue for the device |
| * @mask: alignment mask |
| * |
| * description: |
| * set required memory and length alignment for direct dma transactions. |
| * this is used when building direct io requests for the queue. |
| * |
| **/ |
| void blk_queue_dma_alignment(struct request_queue *q, int mask) |
| { |
| q->dma_alignment = mask; |
| } |
| EXPORT_SYMBOL(blk_queue_dma_alignment); |
| |
| /** |
| * blk_queue_update_dma_alignment - update dma length and memory alignment |
| * @q: the request queue for the device |
| * @mask: alignment mask |
| * |
| * description: |
| * update required memory and length alignment for direct dma transactions. |
| * If the requested alignment is larger than the current alignment, then |
| * the current queue alignment is updated to the new value, otherwise it |
| * is left alone. The design of this is to allow multiple objects |
| * (driver, device, transport etc) to set their respective |
| * alignments without having them interfere. |
| * |
| **/ |
| void blk_queue_update_dma_alignment(struct request_queue *q, int mask) |
| { |
| BUG_ON(mask > PAGE_SIZE); |
| |
| if (mask > q->dma_alignment) |
| q->dma_alignment = mask; |
| } |
| EXPORT_SYMBOL(blk_queue_update_dma_alignment); |
| |
| /** |
| * blk_queue_flush - configure queue's cache flush capability |
| * @q: the request queue for the device |
| * @flush: 0, REQ_FLUSH or REQ_FLUSH | REQ_FUA |
| * |
| * Tell block layer cache flush capability of @q. If it supports |
| * flushing, REQ_FLUSH should be set. If it supports bypassing |
| * write cache for individual writes, REQ_FUA should be set. |
| */ |
| void blk_queue_flush(struct request_queue *q, unsigned int flush) |
| { |
| WARN_ON_ONCE(flush & ~(REQ_FLUSH | REQ_FUA)); |
| |
| if (WARN_ON_ONCE(!(flush & REQ_FLUSH) && (flush & REQ_FUA))) |
| flush &= ~REQ_FUA; |
| |
| q->flush_flags = flush & (REQ_FLUSH | REQ_FUA); |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_flush); |
| |
| void blk_queue_flush_queueable(struct request_queue *q, bool queueable) |
| { |
| q->flush_not_queueable = !queueable; |
| } |
| EXPORT_SYMBOL_GPL(blk_queue_flush_queueable); |
| |
| static int __init blk_settings_init(void) |
| { |
| blk_max_low_pfn = max_low_pfn - 1; |
| blk_max_pfn = max_pfn - 1; |
| return 0; |
| } |
| subsys_initcall(blk_settings_init); |