drm: convert drm context code to use Linux idr

This converts the drm context allocator to an idr, using the new idr
interface features from Kristian.

Fixes from Kristian Hoegsberg <krh@redhat.com>

Signed-off-by: Dave Airlie <airlied@linux.ie>

2 files changed, 33 insertions, 103 deletions

diff --git a/drivers/char/drm/drmP.h b/drivers/char/drm/drmP.h
index 1277693e9ca4..b1cafe36611e 100644
--- a/drivers/char/drm/drmP.h
+++ b/drivers/char/drm/drmP.h
@@ -75,6 +75,8 @@
 #include <asm/pgalloc.h>
 #include "drm.h"
 
+#include <linux/idr.h>
+
 #define __OS_HAS_AGP (defined(CONFIG_AGP) || (defined(CONFIG_AGP_MODULE) && defined(MODULE)))
 #define __OS_HAS_MTRR (defined(CONFIG_MTRR))
 
@@ -676,8 +678,7 @@ struct drm_device {
         int ctx_count;                  /**< Number of context handles */
         struct mutex ctxlist_mutex;     /**< For ctxlist */
 
-        struct drm_map **context_sareas;            /**< per-context SAREA's */
-        int max_context;
+        struct idr ctx_idr;
 
         struct list_head vmalist;       /**< List of vmas (for debugging) */
         struct drm_lock_data lock;      /**< Information on hardware lock */
diff --git a/drivers/char/drm/drm_context.c b/drivers/char/drm/drm_context.c
index 7fc055adec25..61ad986baa8d 100644
--- a/drivers/char/drm/drm_context.c
+++ b/drivers/char/drm/drm_context.c
@@ -53,26 +53,14 @@
  * \param ctx_handle context handle.
  *
  * Clears the bit specified by \p ctx_handle in drm_device::ctx_bitmap and the entry
- * in drm_device::context_sareas, while holding the drm_device::struct_mutex
+ * in drm_device::ctx_idr, while holding the drm_device::struct_mutex
  * lock.
  */
 void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
 {
-        if (ctx_handle < 0)
-                goto failed;
-        if (!dev->ctx_bitmap)
-                goto failed;
-
-        if (ctx_handle < DRM_MAX_CTXBITMAP) {
-                mutex_lock(&dev->struct_mutex);
-                clear_bit(ctx_handle, dev->ctx_bitmap);
-                dev->context_sareas[ctx_handle] = NULL;
-                mutex_unlock(&dev->struct_mutex);
-                return;
-        }
-      failed:
-        DRM_ERROR("Attempt to free invalid context handle: %d\n", ctx_handle);
-        return;
+        mutex_lock(&dev->struct_mutex);
+        idr_remove(&dev->ctx_idr, ctx_handle);
+        mutex_unlock(&dev->struct_mutex);
 }
 
 /**
@@ -81,62 +69,28 @@ void drm_ctxbitmap_free(struct drm_device * dev, int ctx_handle)
  * \param dev DRM device.
  * \return (non-negative) context handle on success or a negative number on failure.
  *
- * Find the first zero bit in drm_device::ctx_bitmap and (re)allocates
- * drm_device::context_sareas to accommodate the new entry while holding the
+ * Allocate a new idr from drm_device::ctx_idr while holding the
  * drm_device::struct_mutex lock.
  */
 static int drm_ctxbitmap_next(struct drm_device * dev)
 {
-        int bit;
-
-        if (!dev->ctx_bitmap)
-                return -1;
+        int new_id;
+        int ret;
 
+again:
+        if (idr_pre_get(&dev->ctx_idr, GFP_KERNEL) == 0) {
+                DRM_ERROR("Out of memory expanding drawable idr\n");
+                return -ENOMEM;
+        }
         mutex_lock(&dev->struct_mutex);
-        bit = find_first_zero_bit(dev->ctx_bitmap, DRM_MAX_CTXBITMAP);
-        if (bit < DRM_MAX_CTXBITMAP) {
-                set_bit(bit, dev->ctx_bitmap);
-                DRM_DEBUG("drm_ctxbitmap_next bit : %d\n", bit);
-                if ((bit + 1) > dev->max_context) {
-                        dev->max_context = (bit + 1);
-                        if (dev->context_sareas) {
-                                struct drm_map **ctx_sareas;
-
-                                ctx_sareas = drm_realloc(dev->context_sareas,
-                                                         (dev->max_context -
-                                                          1) *
-                                                         sizeof(*dev->
-                                                                context_sareas),
-                                                         dev->max_context *
-                                                         sizeof(*dev->
-                                                                context_sareas),
-                                                         DRM_MEM_MAPS);
-                                if (!ctx_sareas) {
-                                        clear_bit(bit, dev->ctx_bitmap);
-                                        mutex_unlock(&dev->struct_mutex);
-                                        return -1;
-                                }
-                                dev->context_sareas = ctx_sareas;
-                                dev->context_sareas[bit] = NULL;
-                        } else {
-                                /* max_context == 1 at this point */
-                                dev->context_sareas =
-                                    drm_alloc(dev->max_context *
-                                              sizeof(*dev->context_sareas),
-                                              DRM_MEM_MAPS);
-                                if (!dev->context_sareas) {
-                                        clear_bit(bit, dev->ctx_bitmap);
-                                        mutex_unlock(&dev->struct_mutex);
-                                        return -1;
-                                }
-                                dev->context_sareas[bit] = NULL;
-                        }
-                }
+        ret = idr_get_new_above(&dev->ctx_idr, NULL,
+                                DRM_RESERVED_CONTEXTS, &new_id);
+        if (ret == -EAGAIN) {
                 mutex_unlock(&dev->struct_mutex);
-                return bit;
+                goto again;
         }
         mutex_unlock(&dev->struct_mutex);
-        return -1;
+        return new_id;
 }
 
 /**
@@ -144,31 +98,11 @@ static int drm_ctxbitmap_next(struct drm_device * dev)
  *
  * \param dev DRM device.
  *
- * Allocates and initialize drm_device::ctx_bitmap and drm_device::context_sareas, while holding
- * the drm_device::struct_mutex lock.
+ * Initialise the drm_device::ctx_idr
  */
 int drm_ctxbitmap_init(struct drm_device * dev)
 {
-        int i;
-        int temp;
-
-        mutex_lock(&dev->struct_mutex);
-        dev->ctx_bitmap = (unsigned long *)drm_alloc(PAGE_SIZE,
-                                                     DRM_MEM_CTXBITMAP);
-        if (dev->ctx_bitmap == NULL) {
-                mutex_unlock(&dev->struct_mutex);
-                return -ENOMEM;
-        }
-        memset((void *)dev->ctx_bitmap, 0, PAGE_SIZE);
-        dev->context_sareas = NULL;
-        dev->max_context = -1;
-        mutex_unlock(&dev->struct_mutex);
-
-        for (i = 0; i < DRM_RESERVED_CONTEXTS; i++) {
-                temp = drm_ctxbitmap_next(dev);
-                DRM_DEBUG("drm_ctxbitmap_init : %d\n", temp);
-        }
-
+        idr_init(&dev->ctx_idr);
         return 0;
 }
 
@@ -177,17 +111,13 @@ int drm_ctxbitmap_init(struct drm_device * dev)
  *
  * \param dev DRM device.
  *
- * Frees drm_device::ctx_bitmap and drm_device::context_sareas, while holding
- * the drm_device::struct_mutex lock.
+ * Free all idr members using drm_ctx_sarea_free helper function
+ * while holding the drm_device::struct_mutex lock.
  */
 void drm_ctxbitmap_cleanup(struct drm_device * dev)
 {
         mutex_lock(&dev->struct_mutex);
-        if (dev->context_sareas)
-                drm_free(dev->context_sareas,
-                         sizeof(*dev->context_sareas) *
-                         dev->max_context, DRM_MEM_MAPS);
-        drm_free((void *)dev->ctx_bitmap, PAGE_SIZE, DRM_MEM_CTXBITMAP);
+        idr_remove_all(&dev->ctx_idr);
         mutex_unlock(&dev->struct_mutex);
 }
 
@@ -206,7 +136,7 @@ void drm_ctxbitmap_cleanup(struct drm_device * dev)
  * \param arg user argument pointing to a drm_ctx_priv_map structure.
  * \return zero on success or a negative number on failure.
  *
- * Gets the map from drm_device::context_sareas with the handle specified and
+ * Gets the map from drm_device::ctx_idr with the handle specified and
  * returns its handle.
  */
 int drm_getsareactx(struct inode *inode, struct file *filp,
@@ -223,13 +153,13 @@ int drm_getsareactx(struct inode *inode, struct file *filp,
                 return -EFAULT;
 
         mutex_lock(&dev->struct_mutex);
-        if (dev->max_context < 0
-            || request.ctx_id >= (unsigned)dev->max_context) {
+
+        map = idr_find(&dev->ctx_idr, request.ctx_id);
+        if (!map) {
                 mutex_unlock(&dev->struct_mutex);
                 return -EINVAL;
         }
 
-        map = dev->context_sareas[request.ctx_id];
         mutex_unlock(&dev->struct_mutex);
 
         request.handle = NULL;
@@ -258,7 +188,7 @@ int drm_getsareactx(struct inode *inode, struct file *filp,
  * \return zero on success or a negative number on failure.
  *
  * Searches the mapping specified in \p arg and update the entry in
- * drm_device::context_sareas with it.
+ * drm_device::ctx_idr with it.
  */
 int drm_setsareactx(struct inode *inode, struct file *filp,
                     unsigned int cmd, unsigned long arg)
@@ -288,11 +218,10 @@ int drm_setsareactx(struct inode *inode, struct file *filp,
         map = r_list->map;
         if (!map)
                 goto bad;
-        if (dev->max_context < 0)
-                goto bad;
-        if (request.ctx_id >= (unsigned)dev->max_context)
+
+        if (IS_ERR(idr_replace(&dev->ctx_idr, map, request.ctx_id)))
                 goto bad;
-        dev->context_sareas[request.ctx_id] = map;
+
         mutex_unlock(&dev->struct_mutex);
         return 0;
 }