From f868089b09b51bd17ee41dedb96f98a1d0952fec Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 29 May 2014 11:45:57 -0400 Subject: [PATCH] NFS: Fix a potential busy wait in nfs_page_group_lock We cannot allow nfs_page_group_lock to use TASK_KILLABLE here, since the loop would cause a busy wait if somebody kills the task. Signed-off-by: Trond Myklebust --- fs/nfs/pagelist.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/fs/nfs/pagelist.c b/fs/nfs/pagelist.c index 0b8446f1008d..a8759825ac76 100644 --- a/fs/nfs/pagelist.c +++ b/fs/nfs/pagelist.c @@ -138,6 +138,12 @@ nfs_iocounter_wait(struct nfs_io_counter *c) return __nfs_iocounter_wait(c); } +static int nfs_wait_bit_uninterruptible(void *word) +{ + io_schedule(); + return 0; +} + /* * nfs_page_group_lock - lock the head of the page group * @req - request in group that is to be locked @@ -148,13 +154,12 @@ void nfs_page_group_lock(struct nfs_page *req) { struct nfs_page *head = req->wb_head; - int err = -EAGAIN; WARN_ON_ONCE(head != head->wb_head); - while (err) - err = wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK, - nfs_wait_bit_killable, TASK_KILLABLE); + wait_on_bit_lock(&head->wb_flags, PG_HEADLOCK, + nfs_wait_bit_uninterruptible, + TASK_UNINTERRUPTIBLE); } /* @@ -410,12 +415,6 @@ void nfs_release_request(struct nfs_page *req) kref_put(&req->wb_kref, nfs_page_group_destroy); } -static int nfs_wait_bit_uninterruptible(void *word) -{ - io_schedule(); - return 0; -} - /** * nfs_wait_on_request - Wait for a request to complete. * @req: request to wait upon. -- GitLab