kernel/linux.git/block/bio.c, branch v7.1-rc5

block: align down bounces bios

2026-05-13T19:55:18+00:00

Just like for the extract user pages path, we need to align down the size to the supported boundary. Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://patch.msgid.link/20260507050153.1298375-3-hch@lst.de Signed-off-by: Jens Axboe

block: pass a minsize argument to bio_iov_iter_bounce

2026-05-13T19:55:06+00:00

When bouncing for block size > PAGE_SIZE file systems that require file system block size alignment (e.g. zoned XFS), the bio needs to be big enough to fit an entire block. Fixes: 8dd5e7c75d7b ("block: add helpers to bounce buffer an iov_iter into bios") Signed-off-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://patch.msgid.link/20260507050153.1298375-2-hch@lst.de Signed-off-by: Jens Axboe

block: only restrict bio allocation gfp mask asked to block

2026-04-21T17:42:12+00:00

If the caller is asking for a non-blocking allocation, we should not further restrict the gfp mask, which just increases the likelihood of failures. Fixes: b520c4eef83d ("block: split bio_alloc_bioset more clearly into a fast and slowpath") Reported-by: Shin'ichiro Kawasaki Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Reviewed-by: Hannes Reinecke Link: https://patch.msgid.link/20260415060813.807659-3-hch@lst.de Signed-off-by: Jens Axboe

block: Add WQ_PERCPU to alloc_workqueue users

2026-04-17T20:38:22+00:00

This continues the effort to refactor workqueue APIs, which began with the introduction of new workqueues and a new alloc_workqueue flag in: commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq") commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag") The refactoring is going to alter the default behavior of alloc_workqueue() to be unbound by default. With the introduction of the WQ_PERCPU flag (equivalent to !WQ_UNBOUND), any alloc_workqueue() caller that doesn’t explicitly specify WQ_UNBOUND must now use WQ_PERCPU. For more details see the Link tag below. In order to keep alloc_workqueue() behavior identical, explicitly request WQ_PERCPU. Link: https://lore.kernel.org/all/20250221112003.1dSuoGyc@linutronix.de/ Suggested-by: Tejun Heo Signed-off-by: Marco Crivellari Link: https://patch.msgid.link/20260223092920.60424-2-marco.crivellari@suse.com Signed-off-by: Jens Axboe

block: relax pgmap check in bio_add_page for compatible zone device pages

2026-04-17T20:37:08+00:00

bio_add_page() and bio_integrity_add_page() reject pages from different dev_pagemaps entirely, returning 0 even when those pages have compatible DMA mapping requirements. This forces callers to start a new bio when buffers span pgmap boundaries, even though the pages could safely coexist as separate bvec entries. This matters for guests where memory is registered through devm_memremap_pages() with MEMORY_DEVICE_GENERIC in multiple calls, creating separate dev_pagemaps for each chunk. When a direct I/O buffer spans two such chunks, bio_add_page() rejects the second page, forcing an unnecessary bio split or I/O failure. Introduce zone_device_pages_compatible() in blk.h to check whether two pages can coexist in the same bio as separate bvec entries. The block DMA iterator (blk_dma_map_iter_start) caches the P2PDMA mapping state from the first segment and applies it to all others, so P2PDMA pages from different pgmaps must not be mixed, and neither must P2PDMA and non-P2PDMA pages. All other combinations (MEMORY_DEVICE_GENERIC pages from different pgmaps, or MEMORY_DEVICE_GENERIC with normal RAM) use the same dma_map_phys path and are safe. Replace the blanket zone_device_pages_have_same_pgmap() rejection with zone_device_pages_compatible(), while keeping zone_device_pages_have_same_pgmap() as a merge guard. Pages from different pgmaps can be added as separate bvec entries but must not be coalesced into the same segment, as that would make it impossible to recover the correct pgmap via page_pgmap(). Fixes: 49580e690755 ("block: add check when merging zone device pages") Cc: stable@vger.kernel.org Signed-off-by: Naman Jain Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20260410153414.4159050-3-namjain@linux.microsoft.com Signed-off-by: Jens Axboe

block: add a bio_submit_or_kill helper

2026-04-07T14:22:24+00:00

Factor the common logic for the ioctl helpers to either submit a bio or end if the process is being killed. As this is now the only user of bio_await_chain, open code that. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://patch.msgid.link/20260407140538.633364-5-hch@lst.de Signed-off-by: Jens Axboe

block: factor out a bio_await helper

2026-04-07T14:22:24+00:00

Add a new helper to wait for a bio and anything chained off it to complete synchronously after submitting it. This factors common code out of submit_bio_wait and bio_await_chain and will also be useful for file system code and thus is exported. Note that this will now set REQ_SYNC also for the bio_await case for consistency. Nothing should look at the flag in the end_io handler, but if something does having the flag set makes more sense. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://patch.msgid.link/20260407140538.633364-4-hch@lst.de Signed-off-by: Jens Axboe

block: unify the synchronous bi_end_io callbacks

2026-04-07T14:22:24+00:00

Put the bio in bio_await_chain after waiting for the completion, and share the now identical callbacks between submit_bio_wait and bio_await_chain. Signed-off-by: Christoph Hellwig Reviewed-by: Bart Van Assche Reviewed-by: Damien Le Moal Link: https://patch.msgid.link/20260407140538.633364-3-hch@lst.de Signed-off-by: Jens Axboe

bio: fix kmemleak false positives from percpu bio alloc cache

2026-04-02T13:07:03+00:00

When a bio is allocated from the mempool with REQ_ALLOC_CACHE set and later completed, bio_put() places it into the per-cpu bio_alloc_cache via bio_put_percpu_cache() instead of freeing it back to the mempool/slab. The slab allocation remains tracked by kmemleak, but the only reference to the bio is through the percpu cache's free_list, which kmemleak fails to trace through percpu memory. This causes kmemleak to report the cached bios as unreferenced objects. Use symmetric kmemleak_free()/kmemleak_alloc() calls to properly track bios across percpu cache transitions: - bio_put_percpu_cache: call kmemleak_free() when a bio enters the cache, unregistering it from kmemleak tracking. - bio_alloc_percpu_cache: call kmemleak_alloc() when a bio is taken from the cache for reuse, re-registering it so that genuine leaks of reused bios remain detectable. - __bio_alloc_cache_prune: call kmemleak_alloc() before bio_free() so that kmem_cache_free()'s internal kmemleak_free() has a matching allocation to pair with. Tested-by: Yi Zhang Signed-off-by: Ming Lei Link: https://patch.msgid.link/20260326144058.2392319-1-ming.lei@redhat.com Signed-off-by: Jens Axboe

block: fix bio_alloc_bioset slowpath GFP handling

2026-03-23T13:58:32+00:00

bio_alloc_bioset() first strips __GFP_DIRECT_RECLAIM from the optimistic fast allocation attempt with try_alloc_gfp(). If that fast path fails, the slowpath checks saved_gfp to decide whether blocking allocation is allowed, but then still calls mempool_alloc() with the stripped gfp mask. That can lead to a NULL bio pointer being passed into bio_init(). Fix the slowpath by using saved_gfp for the bio and bvec mempool allocations. Fixes: b520c4eef83d ("block: split bio_alloc_bioset more clearly into a fast and slowpath") Reported-by: syzbot+09ddb593eea76a158f42@syzkaller.appspotmail.com Signed-off-by: Vasily Gorbik Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/p01.gc6e9ad5845ad.ttca29g@ub.hpns Signed-off-by: Jens Axboe