From: Bart Van Assche <bvanassche@acm.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Christoph Hellwig <hch@lst.de>,
"Martin K . Petersen" <martin.petersen@oracle.com>,
linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
Bart Van Assche <bvanassche@acm.org>,
Dennis Dalessandro <dennis.dalessandro@intel.com>,
Mike Marciniszyn <mike.marciniszyn@intel.com>,
Jason Gunthorpe <jgg@mellanox.com>,
Doug Ledford <dledford@redhat.com>
Subject: [PATCH 8/9] IB/qib: Sign extend without triggering implementation-defined behavior
Date: Mon, 28 Oct 2019 13:06:59 -0700 [thread overview]
Message-ID: <20191028200700.213753-9-bvanassche@acm.org> (raw)
In-Reply-To: <20191028200700.213753-1-bvanassche@acm.org>
From the C standard: "The result of E1 >> E2 is E1 right-shifted E2 bit
positions. If E1 has an unsigned type or if E1 has a signed type and a
nonnegative value, the value of the result is the integral part of the
quotient of E1 / 2E2 . If E1 has a signed type and a negative value, the
resulting value is implementation-defined."
Hence use sign_extend_24_to_32() instead of "<< 8 >> 8".
Cc: Dennis Dalessandro <dennis.dalessandro@intel.com>
Cc: Mike Marciniszyn <mike.marciniszyn@intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Doug Ledford <dledford@redhat.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/infiniband/hw/qib/qib_rc.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/infiniband/hw/qib/qib_rc.c b/drivers/infiniband/hw/qib/qib_rc.c
index aaf7438258fa..2f1beaab6935 100644
--- a/drivers/infiniband/hw/qib/qib_rc.c
+++ b/drivers/infiniband/hw/qib/qib_rc.c
@@ -566,7 +566,7 @@ int qib_make_rc_req(struct rvt_qp *qp, unsigned long *flags)
break;
}
qp->s_sending_hpsn = bth2;
- delta = (((int) bth2 - (int) wqe->psn) << 8) >> 8;
+ delta = sign_extend_24_to_32(bth2 - wqe->psn);
if (delta && delta % QIB_PSN_CREDIT == 0)
bth2 |= IB_BTH_REQ_ACK;
if (qp->s_flags & RVT_S_SEND_ONE) {
--
2.24.0.rc0.303.g954a862665-goog
next prev parent reply other threads:[~2019-10-28 20:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-28 20:06 [PATCH 0/9] Consolidate {get,put}_unaligned_[bl]e24() definitions Bart Van Assche
2019-10-28 20:06 ` [PATCH 1/9] linux/unaligned/byteshift.h: Remove superfluous casts Bart Van Assche
2019-10-28 20:06 ` [PATCH 2/9] c6x: Include <linux/unaligned/generic.h> instead of duplicating it Bart Van Assche
2019-11-07 3:09 ` Bart Van Assche
2019-11-07 13:54 ` Mark Salter
2019-10-28 20:06 ` [PATCH 3/9] treewide: Consolidate {get,put}_unaligned_[bl]e24() definitions Bart Van Assche
2019-10-28 20:06 ` [PATCH 4/9] drivers/iio: Sign extend without triggering implementation-defined behavior Bart Van Assche
2019-10-30 19:43 ` Jonathan Cameron
2019-10-30 20:02 ` Peter Zijlstra
2019-10-30 22:13 ` Douglas Gilbert
2019-10-31 17:55 ` Bart Van Assche
2019-10-28 20:06 ` [PATCH 5/9] scsi/st: Use get_unaligned_signed_be24() Bart Van Assche
2019-10-28 20:06 ` [PATCH 6/9] scsi/trace: Use get_unaligned_be*() Bart Van Assche
2019-10-28 20:06 ` [PATCH 7/9] arm/ecard: Use get_unaligned_le{16,24}() Bart Van Assche
2019-10-28 20:06 ` Bart Van Assche [this message]
2019-10-28 20:07 ` [PATCH 9/9] ASoC/fsl_spdif: Use put_unaligned_be24() instead of open-coding it Bart Van Assche
2019-10-28 20:24 ` Mark Brown
2019-10-28 20:49 ` Bart Van Assche
2019-10-28 21:52 ` [PATCH 0/9] Consolidate {get,put}_unaligned_[bl]e24() definitions Peter Zijlstra
2019-10-28 22:02 ` Bart Van Assche
2019-10-29 1:10 ` Douglas Gilbert
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