Commit 8b88b099 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Linus Torvalds
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libfs: allow error return from simple attributes 



Sometimes simple attributes might need to return an error, e.g. for
acquiring a mutex interruptibly.  In fact we have that situation in
spufs already which is the original user of the simple attributes.  This
patch merged the temporarily forked attributes in spufs back into the
main ones and allows to return errors.

[akpm@linux-foundation.org: build fix]
Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Cc: <stefano.brivio@polimi.it>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Greg KH <greg@kroah.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent efae09f3

arch/avr32/kernel/ocd.c

+11 −7
Original line number Diff line number Diff line
@@ -90,25 +90,29 @@ static struct dentry *ocd_debugfs_DC; 
static struct dentry *ocd_debugfs_DS;

static struct dentry *ocd_debugfs_count;



static u64 ocd_DC_get(void *data)

static int ocd_DC_get(void *data, u64 *val)

{

	return ocd_read(DC);

	*val = ocd_read(DC);

	return 0;

}

static void ocd_DC_set(void *data, u64 val)

static int ocd_DC_set(void *data, u64 val)

{

	ocd_write(DC, val);

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_DC, ocd_DC_get, ocd_DC_set, "0x%08llx\n");



static u64 ocd_DS_get(void *data)

static int ocd_DS_get(void *data, u64 *val)

{

	return ocd_read(DS);

	*val = ocd_read(DS);

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_DS, ocd_DS_get, NULL, "0x%08llx\n");



static u64 ocd_count_get(void *data)

static int ocd_count_get(void *data, u64 *val)

{

	return ocd_count;

	*val = ocd_count;

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_count, ocd_count_get, NULL, "%lld\n");

arch/powerpc/platforms/cell/spufs/file.c

+4 −4
Original line number Diff line number Diff line
@@ -460,7 +460,7 @@ static int spufs_cntl_open(struct inode *inode, struct file *file) 
	if (!i->i_openers++)

		ctx->cntl = inode->i_mapping;

	mutex_unlock(&ctx->mapping_lock);

	return spufs_attr_open(inode, file, spufs_cntl_get,

	return simple_attr_open(inode, file, spufs_cntl_get,

					spufs_cntl_set, "0x%08lx");

}
@@ -470,7 +470,7 @@ spufs_cntl_release(struct inode *inode, struct file *file) 
	struct spufs_inode_info *i = SPUFS_I(inode);

	struct spu_context *ctx = i->i_ctx;



	spufs_attr_release(inode, file);

	simple_attr_close(inode, file);



	mutex_lock(&ctx->mapping_lock);

	if (!--i->i_openers)
@@ -482,8 +482,8 @@ spufs_cntl_release(struct inode *inode, struct file *file) 
static const struct file_operations spufs_cntl_fops = {

	.open = spufs_cntl_open,

	.release = spufs_cntl_release,

	.read = spufs_attr_read,

	.write = spufs_attr_write,

	.read = simple_attr_read,

	.write = simple_attr_write,

	.mmap = spufs_cntl_mmap,

};

fs/debugfs/file.c

+20 −12
Original line number Diff line number Diff line
@@ -56,13 +56,15 @@ const struct inode_operations debugfs_link_operations = { 
	.follow_link    = debugfs_follow_link,

};



static void debugfs_u8_set(void *data, u64 val)

static int debugfs_u8_set(void *data, u64 val)

{

	*(u8 *)data = val;

	return 0;

}

static u64 debugfs_u8_get(void *data)

static int debugfs_u8_get(void *data, u64 *val)

{

	return *(u8 *)data;

	*val = *(u8 *)data;

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_u8, debugfs_u8_get, debugfs_u8_set, "%llu\n");
@@ -97,13 +99,15 @@ struct dentry *debugfs_create_u8(const char *name, mode_t mode, 
}

EXPORT_SYMBOL_GPL(debugfs_create_u8);



static void debugfs_u16_set(void *data, u64 val)

static int debugfs_u16_set(void *data, u64 val)

{

	*(u16 *)data = val;

	return 0;

}

static u64 debugfs_u16_get(void *data)

static int debugfs_u16_get(void *data, u64 *val)

{

	return *(u16 *)data;

	*val = *(u16 *)data;

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_u16, debugfs_u16_get, debugfs_u16_set, "%llu\n");
@@ -138,13 +142,15 @@ struct dentry *debugfs_create_u16(const char *name, mode_t mode, 
}

EXPORT_SYMBOL_GPL(debugfs_create_u16);



static void debugfs_u32_set(void *data, u64 val)

static int debugfs_u32_set(void *data, u64 val)

{

	*(u32 *)data = val;

	return 0;

}

static u64 debugfs_u32_get(void *data)

static int debugfs_u32_get(void *data, u64 *val)

{

	return *(u32 *)data;

	*val = *(u32 *)data;

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_u32, debugfs_u32_get, debugfs_u32_set, "%llu\n");
@@ -179,14 +185,16 @@ struct dentry *debugfs_create_u32(const char *name, mode_t mode, 
}

EXPORT_SYMBOL_GPL(debugfs_create_u32);



static void debugfs_u64_set(void *data, u64 val)

static int debugfs_u64_set(void *data, u64 val)

{

	*(u64 *)data = val;

	return 0;

}



static u64 debugfs_u64_get(void *data)

static int debugfs_u64_get(void *data, u64 *val)

{

	return *(u64 *)data;

	*val = *(u64 *)data;

	return 0;

}

DEFINE_SIMPLE_ATTRIBUTE(fops_u64, debugfs_u64_get, debugfs_u64_set, "%llu\n");

fs/libfs.c

+13 −8
Original line number Diff line number Diff line
@@ -583,8 +583,8 @@ int simple_transaction_release(struct inode *inode, struct file *file) 
/* Simple attribute files */



struct simple_attr {

	u64 (*get)(void *);

	void (*set)(void *, u64);

	int (*get)(void *, u64 *);

	int (*set)(void *, u64);

	char get_buf[24];	/* enough to store a u64 and "\n\0" */

	char set_buf[24];

	void *data;
@@ -595,7 +595,7 @@ struct simple_attr { 
/* simple_attr_open is called by an actual attribute open file operation

 * to set the attribute specific access operations. */

int simple_attr_open(struct inode *inode, struct file *file,

		     u64 (*get)(void *), void (*set)(void *, u64),

		     int (*get)(void *, u64 *), int (*set)(void *, u64),

		     const char *fmt)

{

	struct simple_attr *attr;
@@ -635,14 +635,20 @@ ssize_t simple_attr_read(struct file *file, char __user *buf, 
		return -EACCES;



	mutex_lock(&attr->mutex);

	if (*ppos) /* continued read */

	if (*ppos) {		/* continued read */

		size = strlen(attr->get_buf);

	else	  /* first read */

	} else {		/* first read */

		u64 val;

		ret = attr->get(attr->data, &val);

		if (ret)

			goto out;



		size = scnprintf(attr->get_buf, sizeof(attr->get_buf),

				 attr->fmt,

				 (unsigned long long)attr->get(attr->data));

				 attr->fmt, (unsigned long long)val);

	}



	ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);

out:

	mutex_unlock(&attr->mutex);

	return ret;

}
@@ -657,7 +663,6 @@ ssize_t simple_attr_write(struct file *file, const char __user *buf, 
	ssize_t ret;



	attr = file->private_data;



	if (!attr->set)

		return -EACCES;

include/linux/fs.h

+1 −1
Original line number Diff line number Diff line
@@ -2068,7 +2068,7 @@ __simple_attr_check_format(const char *fmt, ...) 
}



int simple_attr_open(struct inode *inode, struct file *file,

		     u64 (*get)(void *), void (*set)(void *, u64),

		     int (*get)(void *, u64 *), int (*set)(void *, u64),

		     const char *fmt);

int simple_attr_close(struct inode *inode, struct file *file);

ssize_t simple_attr_read(struct file *file, char __user *buf,

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