Commit 01b2d93c authored by Vadim Lobanov's avatar Vadim Lobanov Committed by Linus Torvalds

[PATCH] fdtable: Provide free_fdtable() wrapper

Christoph Hellwig has expressed concerns that the recent fdtable changes
expose the details of the RCU methodology used to release no-longer-used
fdtable structures to the rest of the kernel.  The trivial patch below
addresses these concerns by introducing the appropriate free_fdtable()
calls, which simply wrap the release RCU usage.  Since free_fdtable() is a
one-liner, it makes sense to promote it to an inline helper.
Signed-off-by: default avatarVadim Lobanov <vlobanov@speakeasy.net>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 31fccf7f
...@@ -206,7 +206,7 @@ static int expand_fdtable(struct files_struct *files, int nr) ...@@ -206,7 +206,7 @@ static int expand_fdtable(struct files_struct *files, int nr)
copy_fdtable(new_fdt, cur_fdt); copy_fdtable(new_fdt, cur_fdt);
rcu_assign_pointer(files->fdt, new_fdt); rcu_assign_pointer(files->fdt, new_fdt);
if (cur_fdt->max_fds > NR_OPEN_DEFAULT) if (cur_fdt->max_fds > NR_OPEN_DEFAULT)
call_rcu(&cur_fdt->rcu, free_fdtable_rcu); free_fdtable(cur_fdt);
} else { } else {
/* Somebody else expanded, so undo our attempt */ /* Somebody else expanded, so undo our attempt */
free_fdarr(new_fdt); free_fdarr(new_fdt);
......
...@@ -80,6 +80,11 @@ extern int expand_files(struct files_struct *, int nr); ...@@ -80,6 +80,11 @@ extern int expand_files(struct files_struct *, int nr);
extern void free_fdtable_rcu(struct rcu_head *rcu); extern void free_fdtable_rcu(struct rcu_head *rcu);
extern void __init files_defer_init(void); extern void __init files_defer_init(void);
static inline void free_fdtable(struct fdtable *fdt)
{
call_rcu(&fdt->rcu, free_fdtable_rcu);
}
static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd) static inline struct file * fcheck_files(struct files_struct *files, unsigned int fd)
{ {
struct file * file = NULL; struct file * file = NULL;
......
...@@ -468,7 +468,7 @@ void fastcall put_files_struct(struct files_struct *files) ...@@ -468,7 +468,7 @@ void fastcall put_files_struct(struct files_struct *files)
fdt = files_fdtable(files); fdt = files_fdtable(files);
if (fdt != &files->fdtab) if (fdt != &files->fdtab)
kmem_cache_free(files_cachep, files); kmem_cache_free(files_cachep, files);
call_rcu(&fdt->rcu, free_fdtable_rcu); free_fdtable(fdt);
} }
} }
......
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