IB/core: convert to idr_alloc()

Convert to the much saner new idr interface.

v2: Mike triggered WARN_ON() in idr_preload() because send_mad(),
    which may be used from non-process context, was calling
    idr_preload() unconditionally.  Preload iff @gfp_mask has
    __GFP_WAIT.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Sean Hefty <sean.hefty@intel.com>
Reported-by: "Marciniszyn, Mike" <mike.marciniszyn@intel.com>
Cc: Roland Dreier <roland@kernel.org>
Cc: Sean Hefty <sean.hefty@intel.com>
Cc: Hal Rosenstock <hal.rosenstock@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

6 files changed, 48 insertions, 81 deletions

diff --git a/drivers/infiniband/core/cm.c b/drivers/infiniband/core/cm.c
index 394fea2ba1bc..98281fe5ea4b 100644
--- a/drivers/infiniband/core/cm.c
+++ b/drivers/infiniband/core/cm.c
@@ -382,20 +382,21 @@ static int cm_init_av_by_path(struct ib_sa_path_rec *path, struct cm_av *av)
 static int cm_alloc_id(struct cm_id_private *cm_id_priv)
 {
         unsigned long flags;
-        int ret, id;
+        int id;
         static int next_id;
 
-        do {
-                spin_lock_irqsave(&cm.lock, flags);
-                ret = idr_get_new_above(&cm.local_id_table, cm_id_priv,
-                                        next_id, &id);
-                if (!ret)
-                        next_id = ((unsigned) id + 1) & MAX_IDR_MASK;
-                spin_unlock_irqrestore(&cm.lock, flags);
-        } while( (ret == -EAGAIN) && idr_pre_get(&cm.local_id_table, GFP_KERNEL) );
+        idr_preload(GFP_KERNEL);
+        spin_lock_irqsave(&cm.lock, flags);
+
+        id = idr_alloc(&cm.local_id_table, cm_id_priv, next_id, 0, GFP_NOWAIT);
+        if (id >= 0)
+                next_id = ((unsigned) id + 1) & MAX_IDR_MASK;
+
+        spin_unlock_irqrestore(&cm.lock, flags);
+        idr_preload_end();
 
         cm_id_priv->id.local_id = (__force __be32)id ^ cm.random_id_operand;
-        return ret;
+        return id < 0 ? id : 0;
 }
 
 static void cm_free_id(__be32 local_id)
@@ -3844,7 +3845,6 @@ static int __init ib_cm_init(void)
         cm.remote_sidr_table = RB_ROOT;
         idr_init(&cm.local_id_table);
         get_random_bytes(&cm.random_id_operand, sizeof cm.random_id_operand);
-        idr_pre_get(&cm.local_id_table, GFP_KERNEL);
         INIT_LIST_HEAD(&cm.timewait_list);
 
         ret = class_register(&cm_class);
diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
index d789eea32168..c32eeaa3f3b1 100644
--- a/drivers/infiniband/core/cma.c
+++ b/drivers/infiniband/core/cma.c
@@ -2143,33 +2143,23 @@ static int cma_alloc_port(struct idr *ps, struct rdma_id_private *id_priv,
                           unsigned short snum)
 {
         struct rdma_bind_list *bind_list;
-        int port, ret;
+        int ret;
 
         bind_list = kzalloc(sizeof *bind_list, GFP_KERNEL);
         if (!bind_list)
                 return -ENOMEM;
 
-        do {
-                ret = idr_get_new_above(ps, bind_list, snum, &port);
-        } while ((ret == -EAGAIN) && idr_pre_get(ps, GFP_KERNEL));
-
-        if (ret)
-                goto err1;
-
-        if (port != snum) {
-                ret = -EADDRNOTAVAIL;
-                goto err2;
-        }
+        ret = idr_alloc(ps, bind_list, snum, snum + 1, GFP_KERNEL);
+        if (ret < 0)
+                goto err;
 
         bind_list->ps = ps;
-        bind_list->port = (unsigned short) port;
+        bind_list->port = (unsigned short)ret;
         cma_bind_port(bind_list, id_priv);
         return 0;
-err2:
-        idr_remove(ps, port);
-err1:
+err:
         kfree(bind_list);
-        return ret;
+        return ret == -ENOSPC ? -EADDRNOTAVAIL : ret;
 }
 
 static int cma_alloc_any_port(struct idr *ps, struct rdma_id_private *id_priv)
diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c
index a8905abc56e4..934f45e79e5e 100644
--- a/drivers/infiniband/core/sa_query.c
+++ b/drivers/infiniband/core/sa_query.c
@@ -611,19 +611,21 @@ static void init_mad(struct ib_sa_mad *mad, struct ib_mad_agent *agent)
 
 static int send_mad(struct ib_sa_query *query, int timeout_ms, gfp_t gfp_mask)
 {
+        bool preload = gfp_mask & __GFP_WAIT;
         unsigned long flags;
         int ret, id;
 
-retry:
-        if (!idr_pre_get(&query_idr, gfp_mask))
-                return -ENOMEM;
+        if (preload)
+                idr_preload(gfp_mask);
         spin_lock_irqsave(&idr_lock, flags);
-        ret = idr_get_new(&query_idr, query, &id);
+
+        id = idr_alloc(&query_idr, query, 0, 0, GFP_NOWAIT);
+
         spin_unlock_irqrestore(&idr_lock, flags);
-        if (ret == -EAGAIN)
-                goto retry;
-        if (ret)
-                return ret;
+        if (preload)
+                idr_preload_end();
+        if (id < 0)
+                return id;
 
         query->mad_buf->timeout_ms  = timeout_ms;
         query->mad_buf->context[0] = query;
diff --git a/drivers/infiniband/core/ucm.c b/drivers/infiniband/core/ucm.c
index 49b15ac1987e..f2f63933e8a9 100644
--- a/drivers/infiniband/core/ucm.c
+++ b/drivers/infiniband/core/ucm.c
@@ -176,7 +176,6 @@ static void ib_ucm_cleanup_events(struct ib_ucm_context *ctx)
 static struct ib_ucm_context *ib_ucm_ctx_alloc(struct ib_ucm_file *file)
 {
         struct ib_ucm_context *ctx;
-        int result;
 
         ctx = kzalloc(sizeof *ctx, GFP_KERNEL);
         if (!ctx)
@@ -187,17 +186,10 @@ static struct ib_ucm_context *ib_ucm_ctx_alloc(struct ib_ucm_file *file)
         ctx->file = file;
         INIT_LIST_HEAD(&ctx->events);
 
-        do {
-                result = idr_pre_get(&ctx_id_table, GFP_KERNEL);
-                if (!result)
-                        goto error;
-
-                mutex_lock(&ctx_id_mutex);
-                result = idr_get_new(&ctx_id_table, ctx, &ctx->id);
-                mutex_unlock(&ctx_id_mutex);
-        } while (result == -EAGAIN);
-
-        if (result)
+        mutex_lock(&ctx_id_mutex);
+        ctx->id = idr_alloc(&ctx_id_table, ctx, 0, 0, GFP_KERNEL);
+        mutex_unlock(&ctx_id_mutex);
+        if (ctx->id < 0)
                 goto error;
 
         list_add_tail(&ctx->file_list, &file->ctxs);
diff --git a/drivers/infiniband/core/ucma.c b/drivers/infiniband/core/ucma.c
index 2709ff581392..5ca44cd9b00c 100644
--- a/drivers/infiniband/core/ucma.c
+++ b/drivers/infiniband/core/ucma.c
@@ -145,7 +145,6 @@ static void ucma_put_ctx(struct ucma_context *ctx)
 static struct ucma_context *ucma_alloc_ctx(struct ucma_file *file)
 {
         struct ucma_context *ctx;
-        int ret;
 
         ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
         if (!ctx)
@@ -156,17 +155,10 @@ static struct ucma_context *ucma_alloc_ctx(struct ucma_file *file)
         INIT_LIST_HEAD(&ctx->mc_list);
         ctx->file = file;
 
-        do {
-                ret = idr_pre_get(&ctx_idr, GFP_KERNEL);
-                if (!ret)
-                        goto error;
-
-                mutex_lock(&mut);
-                ret = idr_get_new(&ctx_idr, ctx, &ctx->id);
-                mutex_unlock(&mut);
-        } while (ret == -EAGAIN);
-
-        if (ret)
+        mutex_lock(&mut);
+        ctx->id = idr_alloc(&ctx_idr, ctx, 0, 0, GFP_KERNEL);
+        mutex_unlock(&mut);
+        if (ctx->id < 0)
                 goto error;
 
         list_add_tail(&ctx->list, &file->ctx_list);
@@ -180,23 +172,15 @@ error:
 static struct ucma_multicast* ucma_alloc_multicast(struct ucma_context *ctx)
 {
         struct ucma_multicast *mc;
-        int ret;
 
         mc = kzalloc(sizeof(*mc), GFP_KERNEL);
         if (!mc)
                 return NULL;
 
-        do {
-                ret = idr_pre_get(&multicast_idr, GFP_KERNEL);
-                if (!ret)
-                        goto error;
-
-                mutex_lock(&mut);
-                ret = idr_get_new(&multicast_idr, mc, &mc->id);
-                mutex_unlock(&mut);
-        } while (ret == -EAGAIN);
-
-        if (ret)
+        mutex_lock(&mut);
+        mc->id = idr_alloc(&multicast_idr, mc, 0, 0, GFP_KERNEL);
+        mutex_unlock(&mut);
+        if (mc->id < 0)
                 goto error;
 
         mc->ctx = ctx;
diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index e71d834c922a..a7d00f6b3bc1 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -125,18 +125,17 @@ static int idr_add_uobj(struct idr *idr, struct ib_uobject *uobj)
 {
         int ret;
 
-retry:
-        if (!idr_pre_get(idr, GFP_KERNEL))
-                return -ENOMEM;
-
+        idr_preload(GFP_KERNEL);
         spin_lock(&ib_uverbs_idr_lock);
-        ret = idr_get_new(idr, uobj, &uobj->id);
-        spin_unlock(&ib_uverbs_idr_lock);
 
-        if (ret == -EAGAIN)
-                goto retry;
+        ret = idr_alloc(idr, uobj, 0, 0, GFP_NOWAIT);
+        if (ret >= 0)
+                uobj->id = ret;
 
-        return ret;
+        spin_unlock(&ib_uverbs_idr_lock);
+        idr_preload_end();
+
+        return ret < 0 ? ret : 0;
 }
 
 void idr_remove_uobj(struct idr *idr, struct ib_uobject *uobj)