[CELL] spufs: extension of spu_create to support affinity definition

This patch adds support for additional flags at spu_create, which relate
to the establishment of affinity between contexts and contexts to memory.
A fourth, optional, parameter is supported. This parameter represent
a affinity neighbor of the context being created, and is used when defining
SPU-SPU affinity.
Affinity is represented as a doubly linked list of spu_contexts.

Signed-off-by: Andre Detsch <adetsch@br.ibm.com>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

6 files changed, 188 insertions, 14 deletions

diff --git a/arch/powerpc/platforms/cell/spu_syscalls.c b/arch/powerpc/platforms/cell/spu_syscalls.c
index 261b507a901a..dd2c6688c8aa 100644
--- a/arch/powerpc/platforms/cell/spu_syscalls.c
+++ b/arch/powerpc/platforms/cell/spu_syscalls.c
@@ -34,14 +34,27 @@ struct spufs_calls spufs_calls = {
  * this file is not used and the syscalls directly enter the fs code */
 
 asmlinkage long sys_spu_create(const char __user *name,
-                unsigned int flags, mode_t mode)
+                unsigned int flags, mode_t mode, int neighbor_fd)
 {
         long ret;
         struct module *owner = spufs_calls.owner;
+        struct file *neighbor;
+        int fput_needed;
 
         ret = -ENOSYS;
         if (owner && try_module_get(owner)) {
-                ret = spufs_calls.create_thread(name, flags, mode);
+                if (flags & SPU_CREATE_AFFINITY_SPU) {
+                        neighbor = fget_light(neighbor_fd, &fput_needed);
+                        if (neighbor) {
+                                ret = spufs_calls.create_thread(name, flags,
+                                                                mode, neighbor);
+                                fput_light(neighbor, fput_needed);
+                        }
+                }
+                else {
+                        ret = spufs_calls.create_thread(name, flags,
+                                                        mode, NULL);
+                }
                 module_put(owner);
         }
         return ret;
diff --git a/arch/powerpc/platforms/cell/spufs/context.c b/arch/powerpc/platforms/cell/spufs/context.c
index 6b091ea1d192..a7efb999d65e 100644
--- a/arch/powerpc/platforms/cell/spufs/context.c
+++ b/arch/powerpc/platforms/cell/spufs/context.c
@@ -55,6 +55,7 @@ struct spu_context *alloc_spu_context(struct spu_gang *gang)
         ctx->ops = &spu_backing_ops;
         ctx->owner = get_task_mm(current);
         INIT_LIST_HEAD(&ctx->rq);
+        INIT_LIST_HEAD(&ctx->aff_list);
         if (gang)
                 spu_gang_add_ctx(gang, ctx);
         ctx->cpus_allowed = current->cpus_allowed;
diff --git a/arch/powerpc/platforms/cell/spufs/gang.c b/arch/powerpc/platforms/cell/spufs/gang.c
index 212ea78f9051..0a752ce67c8a 100644
--- a/arch/powerpc/platforms/cell/spufs/gang.c
+++ b/arch/powerpc/platforms/cell/spufs/gang.c
@@ -35,7 +35,9 @@ struct spu_gang *alloc_spu_gang(void)
 
         kref_init(&gang->kref);
         mutex_init(&gang->mutex);
+        mutex_init(&gang->aff_mutex);
         INIT_LIST_HEAD(&gang->list);
+        INIT_LIST_HEAD(&gang->aff_list_head);
 
 out:
         return gang;
@@ -73,6 +75,8 @@ void spu_gang_remove_ctx(struct spu_gang *gang, struct spu_context *ctx)
 {
         mutex_lock(&gang->mutex);
         WARN_ON(ctx->gang != gang);
+        if (!list_empty(&ctx->aff_list))
+                list_del_init(&ctx->aff_list);
         list_del_init(&ctx->gang_list);
         gang->contexts--;
         mutex_unlock(&gang->mutex);
diff --git a/arch/powerpc/platforms/cell/spufs/inode.c b/arch/powerpc/platforms/cell/spufs/inode.c
index 7eb4d6cbcb74..b3d0dd118dd0 100644
--- a/arch/powerpc/platforms/cell/spufs/inode.c
+++ b/arch/powerpc/platforms/cell/spufs/inode.c
@@ -316,11 +316,107 @@ out:
         return ret;
 }
 
-static int spufs_create_context(struct inode *inode,
-                        struct dentry *dentry,
-                        struct vfsmount *mnt, int flags, int mode)
+static struct spu_context *
+spufs_assert_affinity(unsigned int flags, struct spu_gang *gang,
+                                                struct file *filp)
+{
+        struct spu_context *tmp, *neighbor;
+        int count, node;
+        int aff_supp;
+
+        aff_supp = !list_empty(&(list_entry(cbe_spu_info[0].spus.next,
+                                        struct spu, cbe_list))->aff_list);
+
+        if (!aff_supp)
+                return ERR_PTR(-EINVAL);
+
+        if (flags & SPU_CREATE_GANG)
+                return ERR_PTR(-EINVAL);
+
+        if (flags & SPU_CREATE_AFFINITY_MEM &&
+            gang->aff_ref_ctx &&
+            gang->aff_ref_ctx->flags & SPU_CREATE_AFFINITY_MEM)
+                return ERR_PTR(-EEXIST);
+
+        if (gang->aff_flags & AFF_MERGED)
+                return ERR_PTR(-EBUSY);
+
+        neighbor = NULL;
+        if (flags & SPU_CREATE_AFFINITY_SPU) {
+                if (!filp || filp->f_op != &spufs_context_fops)
+                        return ERR_PTR(-EINVAL);
+
+                neighbor = get_spu_context(
+                                SPUFS_I(filp->f_dentry->d_inode)->i_ctx);
+
+                if (!list_empty(&neighbor->aff_list) && !(neighbor->aff_head) &&
+                    !list_is_last(&neighbor->aff_list, &gang->aff_list_head) &&
+                    !list_entry(neighbor->aff_list.next, struct spu_context,
+                    aff_list)->aff_head)
+                        return ERR_PTR(-EEXIST);
+
+                if (gang != neighbor->gang)
+                        return ERR_PTR(-EINVAL);
+
+                count = 1;
+                list_for_each_entry(tmp, &gang->aff_list_head, aff_list)
+                        count++;
+                if (list_empty(&neighbor->aff_list))
+                        count++;
+
+                for (node = 0; node < MAX_NUMNODES; node++) {
+                        if ((cbe_spu_info[node].n_spus - atomic_read(
+                                &cbe_spu_info[node].reserved_spus)) >= count)
+                                break;
+                }
+
+                if (node == MAX_NUMNODES)
+                        return ERR_PTR(-EEXIST);
+        }
+
+        return neighbor;
+}
+
+static void
+spufs_set_affinity(unsigned int flags, struct spu_context *ctx,
+                                        struct spu_context *neighbor)
+{
+        if (flags & SPU_CREATE_AFFINITY_MEM)
+                ctx->gang->aff_ref_ctx = ctx;
+
+        if (flags & SPU_CREATE_AFFINITY_SPU) {
+                if (list_empty(&neighbor->aff_list)) {
+                        list_add_tail(&neighbor->aff_list,
+                                &ctx->gang->aff_list_head);
+                        neighbor->aff_head = 1;
+                }
+
+                if (list_is_last(&neighbor->aff_list, &ctx->gang->aff_list_head)
+                    || list_entry(neighbor->aff_list.next, struct spu_context,
+                                                        aff_list)->aff_head) {
+                        list_add(&ctx->aff_list, &neighbor->aff_list);
+                } else  {
+                        list_add_tail(&ctx->aff_list, &neighbor->aff_list);
+                        if (neighbor->aff_head) {
+                                neighbor->aff_head = 0;
+                                ctx->aff_head = 1;
+                        }
+                }
+
+                if (!ctx->gang->aff_ref_ctx)
+                        ctx->gang->aff_ref_ctx = ctx;
+        }
+}
+
+static int
+spufs_create_context(struct inode *inode, struct dentry *dentry,
+                        struct vfsmount *mnt, int flags, int mode,
+                        struct file *aff_filp)
 {
         int ret;
+        int affinity;
+        struct spu_gang *gang;
+        struct spu_context *neighbor;
 
         ret = -EPERM;
         if ((flags & SPU_CREATE_NOSCHED) &&
@@ -336,9 +432,29 @@ static int spufs_create_context(struct inode *inode,
         if ((flags & SPU_CREATE_ISOLATE) && !isolated_loader)
                 goto out_unlock;
 
+        gang = NULL;
+        neighbor = NULL;
+        affinity = flags & (SPU_CREATE_AFFINITY_MEM | SPU_CREATE_AFFINITY_SPU);
+        if (affinity) {
+                gang = SPUFS_I(inode)->i_gang;
+                ret = -EINVAL;
+                if (!gang)
+                        goto out_unlock;
+                mutex_lock(&gang->aff_mutex);
+                neighbor = spufs_assert_affinity(flags, gang, aff_filp);
+                if (IS_ERR(neighbor)) {
+                        ret = PTR_ERR(neighbor);
+                        goto out_aff_unlock;
+                }
+        }
+
         ret = spufs_mkdir(inode, dentry, flags, mode & S_IRWXUGO);
         if (ret)
-                goto out_unlock;
+                goto out_aff_unlock;
+
+        if (affinity)
+                spufs_set_affinity(flags, SPUFS_I(dentry->d_inode)->i_ctx,
+                                                                neighbor);
 
         /*
          * get references for dget and mntget, will be released
@@ -352,6 +468,9 @@ static int spufs_create_context(struct inode *inode,
                 goto out;
         }
 
+out_aff_unlock:
+        if (affinity)
+                mutex_unlock(&gang->aff_mutex);
 out_unlock:
         mutex_unlock(&inode->i_mutex);
 out:
@@ -450,7 +569,8 @@ out:
 
 static struct file_system_type spufs_type;
 
-long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode)
+long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode,
+                                                        struct file *filp)
 {
         struct dentry *dentry;
         int ret;
@@ -487,7 +607,7 @@ long spufs_create(struct nameidata *nd, unsigned int flags, mode_t mode)
                                         dentry, nd->mnt, mode);
         else
                 return spufs_create_context(nd->dentry->d_inode,
-                                        dentry, nd->mnt, flags, mode);
+                                        dentry, nd->mnt, flags, mode, filp);
 
 out_dput:
         dput(dentry);
diff --git a/arch/powerpc/platforms/cell/spufs/spufs.h b/arch/powerpc/platforms/cell/spufs/spufs.h
index 03e8315f6f9e..36da17987e9c 100644
--- a/arch/powerpc/platforms/cell/spufs/spufs.h
+++ b/arch/powerpc/platforms/cell/spufs/spufs.h
@@ -109,6 +109,9 @@ struct spu_context {
                 unsigned long long class2_intr_base; /* # at last ctx switch */
                 unsigned long long libassist;
         } stats;
+
+        struct list_head aff_list;
+        int aff_head;
 };
 
 struct spu_gang {
@@ -116,8 +119,17 @@ struct spu_gang {
         struct mutex mutex;
         struct kref kref;
         int contexts;
+
+        struct spu_context *aff_ref_ctx;
+        struct list_head aff_list_head;
+        struct mutex aff_mutex;
+        int aff_flags;
 };
 
+/* Flag bits for spu_gang aff_flags */
+#define AFF_OFFSETS_SET         1
+#define AFF_MERGED              2
+
 struct mfc_dma_command {
         int32_t pad;    /* reserved */
         uint32_t lsa;   /* local storage address */
@@ -182,8 +194,8 @@ extern struct tree_descr spufs_dir_nosched_contents[];
 
 /* system call implementation */
 long spufs_run_spu(struct spu_context *ctx, u32 *npc, u32 *status);
-long spufs_create(struct nameidata *nd,
-                         unsigned int flags, mode_t mode);
+long spufs_create(struct nameidata *nd, unsigned int flags,
+                        mode_t mode, struct file *filp);
 extern const struct file_operations spufs_context_fops;
 
 /* gang management */
diff --git a/arch/powerpc/platforms/cell/spufs/syscalls.c b/arch/powerpc/platforms/cell/spufs/syscalls.c
index 13a383c67cae..43f0fb88abbc 100644
--- a/arch/powerpc/platforms/cell/spufs/syscalls.c
+++ b/arch/powerpc/platforms/cell/spufs/syscalls.c
@@ -76,8 +76,8 @@ asmlinkage long sys_spu_run(int fd, __u32 __user *unpc, __u32 __user *ustatus)
 }
 #endif
 
-asmlinkage long sys_spu_create(const char __user *pathname,
-                                        unsigned int flags, mode_t mode)
+asmlinkage long do_spu_create(const char __user *pathname, unsigned int flags,
+                                mode_t mode, struct file *neighbor)
 {
         char *tmp;
         int ret;
@@ -90,7 +90,7 @@ asmlinkage long sys_spu_create(const char __user *pathname,
                 ret = path_lookup(tmp, LOOKUP_PARENT|
                                 LOOKUP_OPEN|LOOKUP_CREATE, &nd);
                 if (!ret) {
-                        ret = spufs_create(&nd, flags, mode);
+                        ret = spufs_create(&nd, flags, mode, neighbor);
                         path_release(&nd);
                 }
                 putname(tmp);
@@ -99,8 +99,32 @@ asmlinkage long sys_spu_create(const char __user *pathname,
         return ret;
 }
 
+#ifndef MODULE
+asmlinkage long sys_spu_create(const char __user *pathname, unsigned int flags,
+                                mode_t mode, int neighbor_fd)
+{
+        int fput_needed;
+        struct file *neighbor;
+        long ret;
+
+        if (flags & SPU_CREATE_AFFINITY_SPU) {
+                ret = -EBADF;
+                neighbor = fget_light(neighbor_fd, &fput_needed);
+                if (neighbor) {
+                        ret = do_spu_create(pathname, flags, mode, neighbor);
+                        fput_light(neighbor, fput_needed);
+                }
+        }
+        else {
+                ret = do_spu_create(pathname, flags, mode, NULL);
+        }
+
+        return ret;
+}
+#endif
+
 struct spufs_calls spufs_calls = {
-        .create_thread = sys_spu_create,
+        .create_thread = do_spu_create,
         .spu_run = do_spu_run,
         .owner = THIS_MODULE,
 };