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author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-03 00:38:10 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-03 00:38:10 +0300 |
commit | 702bfc891db162b99e880da78cc256dac14cfc7f (patch) | |
tree | 5c61da3e5b3d23455eacabe51e81cf612df357cd | |
parent | f016a5405234709938b38e965e02950e51084ac3 (diff) | |
parent | c8d317aa1887b40b188ec3aaa6e9e524333caed1 (diff) | |
download | linux-702bfc891db162b99e880da78cc256dac14cfc7f.tar.xz |
Merge tag 'io_uring-5.9-2020-10-02' of git://git.kernel.dk/linux-block
Pull io_uring fixes from Jens Axboe:
- fix for async buffered reads if read-ahead is fully disabled (Hao)
- double poll match fix
- ->show_fdinfo() potential ABBA deadlock complaint fix
* tag 'io_uring-5.9-2020-10-02' of git://git.kernel.dk/linux-block:
io_uring: fix async buffered reads when readahead is disabled
io_uring: fix potential ABBA deadlock in ->show_fdinfo()
io_uring: always delete double poll wait entry on match
-rw-r--r-- | fs/io_uring.c | 23 | ||||
-rw-r--r-- | mm/filemap.c | 6 |
2 files changed, 23 insertions, 6 deletions
diff --git a/fs/io_uring.c b/fs/io_uring.c index eed0d068904c..aae0ef2ec34d 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -3049,6 +3049,7 @@ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, if (!wake_page_match(wpq, key)) return 0; + req->rw.kiocb.ki_flags &= ~IOCB_WAITQ; list_del_init(&wait->entry); init_task_work(&req->task_work, io_req_task_submit); @@ -3106,6 +3107,7 @@ static bool io_rw_should_retry(struct io_kiocb *req) wait->wait.flags = 0; INIT_LIST_HEAD(&wait->wait.entry); kiocb->ki_flags |= IOCB_WAITQ; + kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_waitq = wait; io_get_req_task(req); @@ -4743,6 +4745,8 @@ static int io_poll_double_wake(struct wait_queue_entry *wait, unsigned mode, if (mask && !(mask & poll->events)) return 0; + list_del_init(&wait->entry); + if (poll && poll->head) { bool done; @@ -8412,11 +8416,19 @@ static int io_uring_show_cred(int id, void *p, void *data) static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) { + bool has_lock; int i; - mutex_lock(&ctx->uring_lock); + /* + * Avoid ABBA deadlock between the seq lock and the io_uring mutex, + * since fdinfo case grabs it in the opposite direction of normal use + * cases. If we fail to get the lock, we just don't iterate any + * structures that could be going away outside the io_uring mutex. + */ + has_lock = mutex_trylock(&ctx->uring_lock); + seq_printf(m, "UserFiles:\t%u\n", ctx->nr_user_files); - for (i = 0; i < ctx->nr_user_files; i++) { + for (i = 0; has_lock && i < ctx->nr_user_files; i++) { struct fixed_file_table *table; struct file *f; @@ -8428,13 +8440,13 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) seq_printf(m, "%5u: <none>\n", i); } seq_printf(m, "UserBufs:\t%u\n", ctx->nr_user_bufs); - for (i = 0; i < ctx->nr_user_bufs; i++) { + for (i = 0; has_lock && i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *buf = &ctx->user_bufs[i]; seq_printf(m, "%5u: 0x%llx/%u\n", i, buf->ubuf, (unsigned int) buf->len); } - if (!idr_is_empty(&ctx->personality_idr)) { + if (has_lock && !idr_is_empty(&ctx->personality_idr)) { seq_printf(m, "Personalities:\n"); idr_for_each(&ctx->personality_idr, io_uring_show_cred, m); } @@ -8449,7 +8461,8 @@ static void __io_uring_show_fdinfo(struct io_ring_ctx *ctx, struct seq_file *m) req->task->task_works != NULL); } spin_unlock_irq(&ctx->completion_lock); - mutex_unlock(&ctx->uring_lock); + if (has_lock) + mutex_unlock(&ctx->uring_lock); } static void io_uring_show_fdinfo(struct seq_file *m, struct file *f) diff --git a/mm/filemap.c b/mm/filemap.c index 5202e38ab79e..99c49eeae71b 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2365,7 +2365,11 @@ readpage: } if (!PageUptodate(page)) { - error = lock_page_killable(page); + if (iocb->ki_flags & IOCB_WAITQ) + error = lock_page_async(page, iocb->ki_waitq); + else + error = lock_page_killable(page); + if (unlikely(error)) goto readpage_error; if (!PageUptodate(page)) { |