Multithreaded application note.

main
Thomas Hellstrom 2006-09-05 19:36:45 +02:00
parent 6042153968
commit e3f54ecdd9
2 changed files with 16 additions and 23 deletions

View File

@ -2750,17 +2750,6 @@ int drmBOMap(int fd, drmBO *buf, unsigned mapFlags, unsigned mapHint,
drm_bo_arg_reply_t *rep = &arg.rep;
int ret = 0;
/*
* At the moment, we don't allow recursive mapping of a buffer, since
* the first mapping may have to be unmapped before this one to succeed.
* This might result in a deadlock. We need a DRM mutex mechanism!!
*/
if (buf->mapCount) {
drmMsg("Recursive mapping is currently not allowed.\n");
return -EAGAIN;
}
/*
* Make sure we have a virtual address of the buffer.
*/
@ -2827,8 +2816,6 @@ int drmBOUnmap(int fd, drmBO *buf)
if (rep->ret)
return rep->ret;
--buf->mapCount;
return 0;
}
@ -2840,11 +2827,6 @@ int drmBOValidate(int fd, drmBO *buf, unsigned flags, unsigned mask,
drm_bo_arg_reply_t *rep = &arg.rep;
int ret = 0;
if (buf->mapCount) {
drmMsg("Cannot validate while buffer is mapped.\n");
return -EAGAIN;
}
arg.handled = 0;
req->handle = buf->handle;
req->mask = flags;
@ -2853,10 +2835,12 @@ int drmBOValidate(int fd, drmBO *buf, unsigned flags, unsigned mask,
req->op = drm_bo_validate;
req->next = 0;
do{
ret = ioctl(fd, DRM_IOCTL_BUFOBJ, &arg);
} while (ret && errno == -EAGAIN);
if (ret)
return ret;
if (!arg.handled)
@ -3008,11 +2992,6 @@ int drmBOValidateList(int fd, drmBOList *list)
if (prevNext)
*prevNext = (unsigned long) arg;
if (node->buf->mapCount) {
drmMsg("Cannot validate while buffer is mapped.\n");
return -EAGAIN;
}
req->next = 0;
prevNext = &req->next;
arg->handled = 0;
@ -3030,6 +3009,7 @@ int drmBOValidateList(int fd, drmBOList *list)
ret = ioctl(fd, DRM_IOCTL_BUFOBJ, &arg);
} while (ret && errno == -EAGAIN);
if (ret)
return -errno;

View File

@ -31,6 +31,18 @@
#include <stddef.h>
#include "drm.h"
/*
* Note on multithreaded applications using this interface.
* Libdrm is not threadsafe, so common buffer, TTM, and fence objects need to
* be protected using an external mutex.
*
* Note: Don't protect the following functions, as it may lead to deadlocks:
* drmBOUnmap(), drmFenceBuffers().
* The kernel is synchronizing and refcounting buffer maps.
* User space only needs to refcount object usage within the same application.
*/
/*
* List macros heavily inspired by the Linux kernel
* list handling. No list looping yet.
@ -82,6 +94,7 @@ typedef struct _drmMMListHead
((__type *)(((char *) (__item)) - offsetof(__type, __field)))
typedef struct _drmBO{
drm_bo_type_t type;
unsigned handle;