From edb7e3ef210d964b2039dc9d1004b1070a800a48 Mon Sep 17 00:00:00 2001 From: Charan Teja Kalla Date: Tue, 14 Feb 2023 18:21:49 +0530 Subject: [PATCH] mm: fadvise: move 'endbyte' calculations to helper function Patch series "mm: shmem: support POSIX_FADV_[WILL|DONT]NEED for shmem files", v7. This patchset aims to implement POSIX_FADV_WILLNEED and POSIX_FADV_DONTNEED advices to shmem files which can be helpful for the drivers who may want to manage the pages of shmem files on their own, like, that are created through shmem_file_setup[_with_mnt](). This patch (of 2): Move the 'endbyte' calculations that determines last byte that fadvise can to a helper function. This is a preparatory change made for shmem_fadvise() functionality in the next patch. No functional changes in this patch. Link: https://lkml.kernel.org/r/cover.1676378702.git.quic_charante@quicinc.com Link: https://lkml.kernel.org/r/22de7e716051abbafc01fab9f479f4d5b03745ca.1676378702.git.quic_charante@quicinc.com Signed-off-by: Charan Teja Kalla Cc: David Rientjes Cc: Hugh Dickins Cc: Mark Hemment Cc: Matthew Wilcox Cc: Pavankumar Kondeti Cc: Shakeel Butt Cc: Suren Baghdasaryan Signed-off-by: Andrew Morton --- mm/fadvise.c | 11 +---------- mm/internal.h | 21 +++++++++++++++++++++ 2 files changed, 22 insertions(+), 10 deletions(-) diff --git a/mm/fadvise.c b/mm/fadvise.c index fb7c5f43fd2a..1b3cac58735c 100644 --- a/mm/fadvise.c +++ b/mm/fadvise.c @@ -65,16 +65,7 @@ int generic_fadvise(struct file *file, loff_t offset, loff_t len, int advice) return 0; } - /* - * Careful about overflows. Len == 0 means "as much as possible". Use - * unsigned math because signed overflows are undefined and UBSan - * complains. - */ - endbyte = (u64)offset + (u64)len; - if (!len || endbyte < len) - endbyte = LLONG_MAX; - else - endbyte--; /* inclusive */ + endbyte = fadvise_calc_endbyte(offset, len); switch (advice) { case POSIX_FADV_NORMAL: diff --git a/mm/internal.h b/mm/internal.h index 2a7ffd9962c4..08ce56dbb1d9 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -657,6 +657,27 @@ static inline void vunmap_range_noflush(unsigned long start, unsigned long end) } #endif /* !CONFIG_MMU */ +/* + * Helper function to get the endbyte of a file that fadvise can operate on. + */ +static inline loff_t fadvise_calc_endbyte(loff_t offset, loff_t len) +{ + loff_t endbyte; + + /* + * Careful about overflows. Len == 0 means "as much as possible". Use + * unsigned math because signed overflows are undefined and UBSan + * complains. + */ + endbyte = (u64)offset + (u64)len; + if (!len || endbyte < len) + endbyte = LLONG_MAX; + else + endbyte--; /* inclusive */ + + return endbyte; +} + /* Memory initialisation debug and verification */ enum mminit_level { MMINIT_WARNING, -- 2.50.1