Commit a892e2d7 authored by Changli Gao's avatar Changli Gao Committed by Linus Torvalds
Browse files

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: default avatarChangli Gao <xiaosuo@gmail.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Avi Kivity <avi@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 06b1e104

fs/file.c

+23 −34
Original line number Diff line number Diff line
@@ -41,26 +41,25 @@ static DEFINE_PER_CPU(struct fdtable_defer, fdtable_defer_list); 


static inline void *alloc_fdmem(unsigned int size)

{

	if (size <= PAGE_SIZE)

		return kmalloc(size, GFP_KERNEL);

	else

	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;

		}

CRA Git | Maintained and supported by SUSTech CRA and CCSE