From a892e2d7dcdfa6c76e60c50a8c7385c65587a2a6 Mon Sep 17 00:00:00 2001 From: Changli Gao Date: Tue, 10 Aug 2010 18:01:35 -0700 Subject: [PATCH] vfs: use kmalloc() to allocate fdmem if possible Use kmalloc() to allocate fdmem if possible. vmalloc() is used as a fallback solution for fdmem allocation. A new helper function __free_fdtable() is introduced to reduce the lines of code. A potential bug, vfree() a memory allocated by kmalloc(), is fixed. [akpm@linux-foundation.org: use __GFP_NOWARN, uninline alloc_fdmem() and free_fdmem()] Signed-off-by: Changli Gao Cc: Alexander Viro Cc: Jiri Slaby Cc: "Paul E. McKenney" Cc: Alexey Dobriyan Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Avi Kivity Cc: Tetsuo Handa Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/file.c | 57 ++++++++++++++++++++++--------------------------------- 1 file changed, 23 insertions(+), 34 deletions(-) diff --git a/fs/file.c b/fs/file.c index cccaead962c2..0be344755c02 100644 --- a/fs/file.c +++ b/fs/file.c @@ -39,28 +39,27 @@ int sysctl_nr_open_max = 1024 * 1024; /* raised later */ */ static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list); -static inline void * alloc_fdmem(unsigned int size) +static inline void *alloc_fdmem(unsigned int size) { - if (size <= PAGE_SIZE) - return kmalloc(size, GFP_KERNEL); - else - return vmalloc(size); + void *data; + + data = kmalloc(size, GFP_KERNEL|__GFP_NOWARN); + if (data != NULL) + return data; + + return vmalloc(size); } -static inline void free_fdarr(struct fdtable *fdt) +static void free_fdmem(void *ptr) { - if (fdt->max_fds <= (PAGE_SIZE / sizeof(struct file *))) - kfree(fdt->fd); - else - vfree(fdt->fd); + is_vmalloc_addr(ptr) ? vfree(ptr) : kfree(ptr); } -static inline void free_fdset(struct fdtable *fdt) +static void __free_fdtable(struct fdtable *fdt) { - if (fdt->max_fds <= (PAGE_SIZE * BITS_PER_BYTE / 2)) - kfree(fdt->open_fds); - else - vfree(fdt->open_fds); + free_fdmem(fdt->fd); + free_fdmem(fdt->open_fds); + kfree(fdt); } static void free_fdtable_work(struct work_struct *work) @@ -75,9 +74,8 @@ static void free_fdtable_work(struct work_struct *work) spin_unlock_bh(&f->lock); while(fdt) { struct fdtable *next = fdt->next; - vfree(fdt->fd); - free_fdset(fdt); - kfree(fdt); + + __free_fdtable(fdt); fdt = next; } } @@ -98,7 +96,7 @@ void free_fdtable_rcu(struct rcu_head *rcu) container_of(fdt, struct files_struct, fdtab)); return; } - if (fdt->max_fds <= (PAGE_SIZE / sizeof(struct file *))) { + if (!is_vmalloc_addr(fdt->fd) && !is_vmalloc_addr(fdt->open_fds)) { kfree(fdt->fd); kfree(fdt->open_fds); kfree(fdt); @@ -183,7 +181,7 @@ static struct fdtable * alloc_fdtable(unsigned int nr) return fdt; out_arr: - free_fdarr(fdt); + free_fdmem(fdt->fd); out_fdt: kfree(fdt); out: @@ -213,9 +211,7 @@ static int expand_fdtable(struct files_struct *files, int nr) * caller and alloc_fdtable(). Cheaper to catch it here... */ if (unlikely(new_fdt->max_fds <= nr)) { - free_fdarr(new_fdt); - free_fdset(new_fdt); - kfree(new_fdt); + __free_fdtable(new_fdt); return -EMFILE; } /* @@ -231,9 +227,7 @@ static int expand_fdtable(struct files_struct *files, int nr) free_fdtable(cur_fdt); } else { /* Somebody else expanded, so undo our attempt */ - free_fdarr(new_fdt); - free_fdset(new_fdt); - kfree(new_fdt); + __free_fdtable(new_fdt); } return 1; } @@ -323,11 +317,8 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) while (unlikely(open_files > new_fdt->max_fds)) { spin_unlock(&oldf->file_lock); - if (new_fdt != &newf->fdtab) { - free_fdarr(new_fdt); - free_fdset(new_fdt); - kfree(new_fdt); - } + if (new_fdt != &newf->fdtab) + __free_fdtable(new_fdt); new_fdt = alloc_fdtable(open_files - 1); if (!new_fdt) { @@ -337,9 +328,7 @@ struct files_struct *dup_fd(struct files_struct *oldf, int *errorp) /* beyond sysctl_nr_open; nothing to do */ if (unlikely(new_fdt->max_fds < open_files)) { - free_fdarr(new_fdt); - free_fdset(new_fdt); - kfree(new_fdt); + __free_fdtable(new_fdt); *errorp = -EMFILE; goto out_release; } -- 2.20.1