(6/20/12 2:31 AM), Wanlong Gao wrote: > On 06/16/2012 04:36 AM, kosaki.motohiro@xxxxxxxxx wrote: >> From: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> >> >> Eric Wong reported his test suite was fail when /tmp is tmpfs. >> >> https://lkml.org/lkml/2012/2/24/479 >> >> Current,input check of POSIX_FADV_WILLNEED has two problems. >> >> 1) require a_ops->readpage. >> But in fact, force_page_cache_readahead() only require >> a target filesystem has either ->readpage or ->readpages. >> 2) return -EINVAL when filesystem don't have ->readpage. >> But, posix says, it should be retrieved a hint. Thus fadvise() >> should return 0 if filesystem has no optimization way. >> Especially, userland application don't know a filesystem type >> of TMPDIR directory as Eric pointed out. Then, userland can't >> avoid this error. We shouldn't encourage to ignore syscall >> return value. >> >> Thus, this patch change a return value to 0 when filesytem don't >> support readahead. >> >> Cc: linux-mm@xxxxxxxxx >> Cc: Hugh Dickins <hughd@xxxxxxxxxx> >> Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> >> Cc: Hillf Danton <dhillf@xxxxxxxxx> >> Signed-off-by: Eric Wong <normalperson@xxxxxxxx> >> Tested-by: Eric Wong <normalperson@xxxxxxxx> >> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx> >> --- >> mm/fadvise.c | 18 +++++++----------- >> 1 files changed, 7 insertions(+), 11 deletions(-) >> >> diff --git a/mm/fadvise.c b/mm/fadvise.c >> index 469491e..33e6baf 100644 >> --- a/mm/fadvise.c >> +++ b/mm/fadvise.c >> @@ -93,11 +93,6 @@ SYSCALL_DEFINE(fadvise64_64)(int fd, loff_t offset, loff_t len, int advice) >> spin_unlock(&file->f_lock); >> break; >> case POSIX_FADV_WILLNEED: >> - if (!mapping->a_ops->readpage) { >> - ret = -EINVAL; >> - break; >> - } > > Why not check both readpage and readpages, if they are not here, > just beak and no following force_page_cache_readahead ? They are checked in force_page_cache_readahead. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>