[PATCH v4 2/3] fs: Convert kiocb rw_hint from enum to u16
From: <hidden>
Date: 2018-05-17 20:38:26
Also in:
linux-block, linux-fsdevel, lkml
Subsystem:
filesystems (vfs and infrastructure), the rest · Maintainers:
Alexander Viro, Christian Brauner, Linus Torvalds
From: Adam Manzanares <redacted> In order to avoid kiocb bloat for per command iopriority support, rw_hint is converted from enum to a u16. Added a guard around ki_hint assigment. Signed-off-by: Adam Manzanares <redacted> --- include/linux/fs.h | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 760d8da1b6c7..7a90ce387e00 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h@@ -284,6 +284,8 @@ enum rw_hint { WRITE_LIFE_EXTREME = RWH_WRITE_LIFE_EXTREME, }; +#define MAX_KI_HINT ((1 << 16) - 1) /* ki_hint type is u16 */ + #define IOCB_EVENTFD (1 << 0) #define IOCB_APPEND (1 << 1) #define IOCB_DIRECT (1 << 2)
@@ -299,7 +301,7 @@ struct kiocb { void (*ki_complete)(struct kiocb *iocb, long ret, long ret2); void *private; int ki_flags; - enum rw_hint ki_hint; + u16 ki_hint; } __randomize_layout; static inline bool is_sync_kiocb(struct kiocb *kiocb)
@@ -1927,12 +1929,21 @@ static inline enum rw_hint file_write_hint(struct file *file) static inline int iocb_flags(struct file *file); +/* ki_hint changed from enum to u16, make sure rw_hint fits into u16 */ +static inline u16 ki_hint_valid(enum rw_hint hint) +{ + if (hint > MAX_KI_HINT) + return 0; + + return hint; +} + static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp) { *kiocb = (struct kiocb) { .ki_filp = filp, .ki_flags = iocb_flags(filp), - .ki_hint = file_write_hint(filp), + .ki_hint = ki_hint_valid(file_write_hint(filp)), }; }
--
2.15.1
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