linux-kernel - [PATCH 4.13 031/109] crypto: scompress - dont sleep with preemption disabled

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Date:   Sun, 24 Sep 2017 22:32:52 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Herbert Xu <herbert@...dor.apana.org.au>
Subject: [PATCH 4.13 031/109] crypto: scompress - dont sleep with preemption disabled

4.13-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ard Biesheuvel <ard.biesheuvel@...aro.org>

commit 3c08377262880afc1621ab9cb6dbe7df47a6033d upstream.

Due to the use of per-CPU buffers, scomp_acomp_comp_decomp() executes
with preemption disabled, and so whether the CRYPTO_TFM_REQ_MAY_SLEEP
flag is set is irrelevant, since we cannot sleep anyway. So disregard
the flag, and use GFP_ATOMIC unconditionally.

Signed-off-by: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Signed-off-by: Herbert Xu <herbert@...dor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 crypto/scompress.c |    4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

--- a/crypto/scompress.c
+++ b/crypto/scompress.c
@@ -211,9 +211,7 @@ static int scomp_acomp_comp_decomp(struc
 					      scratch_dst, &req->dlen, *ctx);
 	if (!ret) {
 		if (!req->dst) {
-			req->dst = crypto_scomp_sg_alloc(req->dlen,
-				   req->base.flags & CRYPTO_TFM_REQ_MAY_SLEEP ?
-				   GFP_KERNEL : GFP_ATOMIC);
+			req->dst = crypto_scomp_sg_alloc(req->dlen, GFP_ATOMIC);
 			if (!req->dst)
 				goto out;
 		}