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Commit c30dbb9c authored by Sage Weil's avatar Sage Weil
Browse files

ceph: ref counted buffer 



struct ceph_buffer is a simple ref-counted buffer.  We transparently
choose between kmalloc for small buffers and vmalloc for large ones.

This is currently used only for allocating memory for xattr data.

Signed-off-by: default avatarSage Weil <sage@newdream.net>
parent de57606c

fs/ceph/buffer.c

0 → 100644
+34 −0
Original line number Original line Diff line number Diff line 


#include "ceph_debug.h"

#include "buffer.h"



struct ceph_buffer *ceph_buffer_new(gfp_t gfp)

{

	struct ceph_buffer *b;



	b = kmalloc(sizeof(*b), gfp);

	if (!b)

		return NULL;

	atomic_set(&b->nref, 1);

	b->vec.iov_base = NULL;

	b->vec.iov_len = 0;

	b->alloc_len = 0;

	return b;

}



int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp)

{

	b->vec.iov_base = kmalloc(len, gfp | __GFP_NOWARN);

	if (b->vec.iov_base) {

		b->is_vmalloc = false;

	} else {

		b->vec.iov_base = __vmalloc(len, gfp, PAGE_KERNEL);

		b->is_vmalloc = true;

	}

	if (!b->vec.iov_base)

		return -ENOMEM;

	b->alloc_len = len;

	b->vec.iov_len = len;

	return 0;

}

fs/ceph/buffer.h

0 → 100644
+55 −0
Original line number Original line Diff line number Diff line 
#ifndef __FS_CEPH_BUFFER_H

#define __FS_CEPH_BUFFER_H



#include <linux/mm.h>

#include <linux/vmalloc.h>

#include <linux/types.h>

#include <linux/uio.h>



/*

 * a simple reference counted buffer.

 *

 * use kmalloc for small sizes (<= one page), vmalloc for larger

 * sizes.

 */

struct ceph_buffer {

	atomic_t nref;

	struct kvec vec;

	size_t alloc_len;

	bool is_vmalloc;

};



struct ceph_buffer *ceph_buffer_new(gfp_t gfp);

int ceph_buffer_alloc(struct ceph_buffer *b, int len, gfp_t gfp);



static inline struct ceph_buffer *ceph_buffer_get(struct ceph_buffer *b)

{

	atomic_inc(&b->nref);

	return b;

}



static inline void ceph_buffer_put(struct ceph_buffer *b)

{

	if (b && atomic_dec_and_test(&b->nref)) {

		if (b->vec.iov_base) {

			if (b->is_vmalloc)

				vfree(b->vec.iov_base);

			else

				kfree(b->vec.iov_base);

		}

		kfree(b);

	}

}



static inline struct ceph_buffer *ceph_buffer_new_alloc(int len, gfp_t gfp)

{

	struct ceph_buffer *b = ceph_buffer_new(gfp);



	if (b && ceph_buffer_alloc(b, len, gfp) < 0) {

		ceph_buffer_put(b);

		b = NULL;

	}

	return b;

}



#endif