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Commit d7fb2c38 authored by Paolo 'Blaisorblade' Giarrusso's avatar Paolo 'Blaisorblade' Giarrusso Committed by Linus Torvalds
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[PATCH] uml ubd driver: change ubd_lock to be a mutex 



This lock protects ubd setup and teardown, so is only used in process context;
beyond that, during such setup memory allocations must be performed and some
generic functions which can sleep must be called (such as add_disk()).  So the
only correct solution is to make it a mutex instead of a spin_lock.  No other
change is done - this lock must be acquired in different places but it's done
afterwards.

Signed-off-by: default avatarPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 5f75a4f8

arch/um/drivers/ubd_kern.c

+12 −11
Original line number Diff line number Diff line
@@ -107,7 +107,8 @@ static inline void ubd_set_bit(__u64 bit, unsigned char *data) 
#define DRIVER_NAME "uml-blkdev"



static DEFINE_SPINLOCK(ubd_io_lock);

static DEFINE_SPINLOCK(ubd_lock);



static DEFINE_MUTEX(ubd_lock);



static void (*do_ubd)(void);
@@ -314,7 +315,7 @@ static int ubd_setup_common(char *str, int *index_out) 
		}



		err = 1;

 		spin_lock(&ubd_lock);

 		mutex_lock(&ubd_lock);

 		if(fake_major != MAJOR_NR){

 			printk(KERN_ERR "Can't assign a fake major twice\n");

 			goto out1;
@@ -326,7 +327,7 @@ static int ubd_setup_common(char *str, int *index_out) 
		       major);

 		err = 0;

 	out1:

 		spin_unlock(&ubd_lock);

 		mutex_unlock(&ubd_lock);

		return(err);

	}
@@ -343,7 +344,7 @@ static int ubd_setup_common(char *str, int *index_out) 
	}



	err = 1;

	spin_lock(&ubd_lock);

	mutex_lock(&ubd_lock);



	ubd_dev = &ubd_devs[n];

	if(ubd_dev->file != NULL){
@@ -405,7 +406,7 @@ static int ubd_setup_common(char *str, int *index_out) 
	ubd_dev->cow.file = backing_file;

	ubd_dev->boot_openflags = flags;

out:

	spin_unlock(&ubd_lock);

	mutex_unlock(&ubd_lock);

	return(err);

}
@@ -710,11 +711,11 @@ static int ubd_config(char *str) 
	}

	if(n == -1) return(0);



 	spin_lock(&ubd_lock);

 	mutex_lock(&ubd_lock);

	err = ubd_add(n);

	if(err)

		ubd_devs[n].file = NULL;

 	spin_unlock(&ubd_lock);

 	mutex_unlock(&ubd_lock);



	return(err);

}
@@ -731,7 +732,7 @@ static int ubd_get_config(char *name, char *str, int size, char **error_out) 
	}



	ubd_dev = &ubd_devs[n];

	spin_lock(&ubd_lock);

	mutex_lock(&ubd_lock);



	if(ubd_dev->file == NULL){

		CONFIG_CHUNK(str, size, len, "", 1);
@@ -747,7 +748,7 @@ static int ubd_get_config(char *name, char *str, int size, char **error_out) 
	else CONFIG_CHUNK(str, size, len, "", 1);



 out:

	spin_unlock(&ubd_lock);

	mutex_unlock(&ubd_lock);

	return(len);

}
@@ -766,7 +767,7 @@ static int ubd_remove(int n) 
	struct ubd *ubd_dev;

	int err = -ENODEV;



	spin_lock(&ubd_lock);

	mutex_lock(&ubd_lock);



	if(ubd_gendisk[n] == NULL)

		goto out;
@@ -795,7 +796,7 @@ static int ubd_remove(int n) 
	*ubd_dev = ((struct ubd) DEFAULT_UBD);

	err = 0;

out:

	spin_unlock(&ubd_lock);

	mutex_unlock(&ubd_lock);

	return err;

}