Messages in this thread | | | Date | Wed, 3 Jan 2018 02:08:05 +0000 | From | Al Viro <> | Subject | Re: [PATCH] ext4: Remove repeated test in ext4_file_read_iter. |
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On Wed, Dec 27, 2017 at 04:19:58PM +0800, Sean Fu wrote: > generic_file_read_iter has done the count test. > So ext4_file_read_iter don't need to test the count repeatedly.
Huh? You do realize that generic_file_read_iter() is not the only variant possible there, right?
static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to) { struct inode *inode = file_inode(iocb->ki_filp); ssize_t ret;
if (!inode_trylock_shared(inode)) { if (iocb->ki_flags & IOCB_NOWAIT) return -EAGAIN; inode_lock_shared(inode); }
... and now IOCB_NOWAIT read with zero count can fail with -EAGAIN.
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