diff mbox

[4/5] IB/hfi1: Use memdup_user() rather than duplicating its implementation in hfi1_user_sdma_process_request()

Message ID b19e44b3-601f-c642-b8d3-12c000511ce2@users.sourceforge.net (mailing list archive)
State Not Applicable
Headers show

Commit Message

SF Markus Elfring Feb. 10, 2017, 9:04 p.m. UTC
From: Markus Elfring <elfring@users.sourceforge.net>
Date: Fri, 10 Feb 2017 21:01:55 +0100

Reuse existing functionality from memdup_user() instead of keeping
duplicate source code.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
---
 drivers/infiniband/hw/hfi1/user_sdma.c | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

Comments

Dennis Dalessandro Feb. 11, 2017, 3:32 p.m. UTC | #1
On 02/10/2017 04:04 PM, SF Markus Elfring wrote:
> From: Markus Elfring <elfring@users.sourceforge.net>
> Date: Fri, 10 Feb 2017 21:01:55 +0100
>
> Reuse existing functionality from memdup_user() instead of keeping
> duplicate source code.
>
> Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>

Thanks for the patch, but this one is already taken care of along with 
other similar uses of kmalloc/copy:

http://marc.info/?l=linux-rdma&m=148656088729538&w=2

Will review the rest of the patch series soon.

-Denny
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SF Markus Elfring Feb. 13, 2017, 9:50 a.m. UTC | #2
> Thanks for the patch, but this one is already taken care of along with other similar uses of kmalloc/copy:
> http://marc.info/?l=linux-rdma&m=148656088729538&w=2

Thanks for your information.

The shown source code is reasonable in the update step “[PATCH 27/27] IB/hfi1:
Code reuse with memdup_copy”.
https://patchwork.kernel.org/patch/9562565/
https://lkml.kernel.org/r/<20170208132830.16442.93943.stgit@scvm10.sc.intel.com>

I find the commit subject and message partly inappropriate.
How do you think about to mention other function names there?

Regards,
Markus
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Dan Carpenter Feb. 13, 2017, 10:53 a.m. UTC | #3
On Sat, Feb 11, 2017 at 10:32:59AM -0500, Dennis Dalessandro wrote:
> On 02/10/2017 04:04 PM, SF Markus Elfring wrote:
> >From: Markus Elfring <elfring@users.sourceforge.net>
> >Date: Fri, 10 Feb 2017 21:01:55 +0100
> >
> >Reuse existing functionality from memdup_user() instead of keeping
> >duplicate source code.
> >
> >Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
> 
> Thanks for the patch, but this one is already taken care of along
> with other similar uses of kmalloc/copy:
> 
> http://marc.info/?l=linux-rdma&m=148656088729538&w=2
> 

Michael's patch doesn't change user_sdma_free_request() so it introduces
a kfreeing an error pointer bug.

regards,
dan carpenter

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SF Markus Elfring Feb. 13, 2017, 11:12 a.m. UTC | #4
>> Thanks for the patch, but this one is already taken care of along
>> with other similar uses of kmalloc/copy:
>>
>> http://marc.info/?l=linux-rdma&m=148656088729538&w=2
>>
> 
> Michael's patch doesn't change user_sdma_free_request() so it introduces
> a kfreeing an error pointer bug.

Did you notice that another local variable “tmp” was introduced in the update step
“[PATCH 27/27] IB/hfi1: Code reuse with memdup_copy” so that
the mentioned function will usually get a null pointer after a failure there?

Regards,
Markus
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Dan Carpenter Feb. 13, 2017, 2:01 p.m. UTC | #5
On Mon, Feb 13, 2017 at 12:12:51PM +0100, SF Markus Elfring wrote:
> >> Thanks for the patch, but this one is already taken care of along
> >> with other similar uses of kmalloc/copy:
> >>
> >> http://marc.info/?l=linux-rdma&m=148656088729538&w=2
> >>
> > 
> > Michael's patch doesn't change user_sdma_free_request() so it introduces
> > a kfreeing an error pointer bug.
> 
> Did you notice that another local variable “tmp” was introduced in the update step
> “[PATCH 27/27] IB/hfi1: Code reuse with memdup_copy” so that
> the mentioned function will usually get a null pointer after a failure there?
> 

Ah right.  Thanks.  I missed that.

regards,
dan carpenter

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diff mbox

Patch

diff --git a/drivers/infiniband/hw/hfi1/user_sdma.c b/drivers/infiniband/hw/hfi1/user_sdma.c
index 991e7f3d8e18..5a73d738f2ba 100644
--- a/drivers/infiniband/hw/hfi1/user_sdma.c
+++ b/drivers/infiniband/hw/hfi1/user_sdma.c
@@ -731,23 +731,18 @@  int hfi1_user_sdma_process_request(struct file *fp, struct iovec *iovec,
 			ret = -EINVAL;
 			goto free_req;
 		}
-		req->tids = kcalloc(ntids, sizeof(*req->tids), GFP_KERNEL);
-		if (!req->tids) {
-			ret = -ENOMEM;
-			goto free_req;
-		}
 		/*
 		 * We have to copy all of the tids because they may vary
 		 * in size and, therefore, the TID count might not be
 		 * equal to the pkt count. However, there is no way to
 		 * tell at this point.
 		 */
-		ret = copy_from_user(req->tids, iovec[idx].iov_base,
-				     ntids * sizeof(*req->tids));
-		if (ret) {
+		req->tids = memdup_user(iovec[idx].iov_base,
+					sizeof(*req->tids) * ntids);
+		if (IS_ERR(req->tids)) {
+			ret = PTR_ERR(req->tids);
 			SDMA_DBG(req, "Failed to copy %d TIDs (%d)",
 				 ntids, ret);
-			ret = -EFAULT;
 			goto free_req;
 		}
 		req->n_tids = ntids;
@@ -1606,7 +1601,8 @@  static void user_sdma_free_request(struct user_sdma_request *req, bool unpin)
 				atomic_dec(&node->refcount);
 		}
 	}
-	kfree(req->tids);
+	if (!IS_ERR(req->tids))
+		kfree(req->tids);
 	clear_bit(req->info.comp_idx, req->pq->req_in_use);
 }