Re: [PATCH][linux-next] soc: fsl: dpio: Unsigned compared against 0 in
From: Ioana Ciornei <ioana.ciornei@nxp.com>
Date: 2021-10-19 09:09:20
Also in:
linux-arm-kernel, lkml
Subject: [PATCH][linux-next] soc: fsl: dpio: Unsigned compared against 0 in
Coverity complains of unsigned compare against 0. There are 2 cases in
this function:
1821 itp = (irq_holdoff * 1000) / p->desc->qman_256_cycles_per_ns;
CID 121131 (#1 of 1): Unsigned compared against 0 (NO_EFFECT)
unsigned_compare: This less-than-zero comparison of an unsigned value is never true. itp < 0U.
1822 if (itp < 0 || itp > 4096) {
1823 max_holdoff = (p->desc->qman_256_cycles_per_ns * 4096) / 1000;
1824 pr_err("irq_holdoff must be between 0..%dus\n", max_holdoff);
1825 return -EINVAL;
1826 }
1827
unsigned_compare: This less-than-zero comparison of an unsigned value is never true. irq_threshold < 0U.
1828 if (irq_threshold >= p->dqrr.dqrr_size || irq_threshold < 0) {
1829 pr_err("irq_threshold must be between 0..%d\n",
1830 p->dqrr.dqrr_size - 1);
1831 return -EINVAL;
1832 }
Fix this by checking for 0. Also fix a minor comment typo.
Fixes ed1d2143fee53755ec601eb4d48a337a93933f71 ("soc: fsl: dpio: add support for
irq coalescing per software portal")
I think this should be formatted as following:
Fixes: ed1d2143fee5 ("soc: fsl: dpio: add support for irq coalescing per software portal")
Cc: Roy Pledge <redacted> Cc: Li Yang <redacted> Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-arm-kernel@lists.infradead.org Signed-off-by: Tim Gardner <redacted> --- I'm not 100% sure this is the right way to fix the warning, but according to the pr_err() comments these values should never be 0.
These threshold values can be 0, the pr_err comment tries to say that those are the ranges, 0 and the maximum included.
quoted hunk ↗ jump to hunk
--- drivers/soc/fsl/dpio/qbman-portal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)diff --git a/drivers/soc/fsl/dpio/qbman-portal.c b/drivers/soc/fsl/dpio/qbman-portal.c index d3c58df6240d..b768a14bb271 100644 --- a/drivers/soc/fsl/dpio/qbman-portal.c +++ b/drivers/soc/fsl/dpio/qbman-portal.c@@ -1816,16 +1816,16 @@ int qbman_swp_set_irq_coalescing(struct qbman_swp *p, u32 irq_threshold, u32 itp, max_holdoff; /* Convert irq_holdoff value from usecs to 256 QBMAN clock cycles - * increments. This depends to the QBMAN internal frequency. + * increments. This depends on the QBMAN internal frequency. */ itp = (irq_holdoff * 1000) / p->desc->qman_256_cycles_per_ns; - if (itp < 0 || itp > 4096) { + if (!itp || itp > 4096) { max_holdoff = (p->desc->qman_256_cycles_per_ns * 4096) / 1000; pr_err("irq_holdoff must be between 0..%dus\n", max_holdoff); return -EINVAL; } - if (irq_threshold >= p->dqrr.dqrr_size || irq_threshold < 0) { + if (irq_threshold >= p->dqrr.dqrr_size || !irq_threshold) { pr_err("irq_threshold must be between 0..%d\n", p->dqrr.dqrr_size - 1); return -EINVAL;
These 'value < 0' checks should be removed all together. Somehow I missed that those are unsigned values. Anyhow, thanks a lot that you spotted this. Could you please sent the v2 towards the net-next tree since that's the tree that adds the fixed patch? Thanks. -Ioana