From 818a76a55d6e9e7ec7568ae580390e941da84b62 Mon Sep 17 00:00:00 2001 From: Tim Gardner Date: Tue, 19 Oct 2021 06:19:25 -0600 Subject: [PATCH] soc: fsl: dpio: Unsigned compared against 0 in qbman_swp_set_irq_coalescing() 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 removing the comparisons altogether as they are incorrect. Zero is a possible value in either case. Also fix a minor comment typo and update the 2 pr_err() calls to use %u formatting as well as be more precise regarding the exact error. Fixes: ed1d2143fee5 ("soc: fsl: dpio: add support for irq coalescing per software portal") Cc: Ioana Ciornei Cc: Roy Pledge Cc: Li Yang Cc: linux-kernel@vger.kernel.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-arm-kernel@lists.infradead.org Cc: netdev@vger.kernel.org Signed-off-by: Tim Gardner Tested-by: Ioana Ciornei Reviewed-by: Ioana Ciornei Signed-off-by: David S. Miller --- drivers/soc/fsl/dpio/qbman-portal.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/drivers/soc/fsl/dpio/qbman-portal.c b/drivers/soc/fsl/dpio/qbman-portal.c index d3c58df6240d..3474bf5f88d5 100644 --- a/drivers/soc/fsl/dpio/qbman-portal.c +++ b/drivers/soc/fsl/dpio/qbman-portal.c @@ -1816,18 +1816,17 @@ 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 > 4096) { max_holdoff = (p->desc->qman_256_cycles_per_ns * 4096) / 1000; - pr_err("irq_holdoff must be between 0..%dus\n", max_holdoff); + pr_err("irq_holdoff must be <= %uus\n", max_holdoff); return -EINVAL; } - if (irq_threshold >= p->dqrr.dqrr_size || irq_threshold < 0) { - pr_err("irq_threshold must be between 0..%d\n", - p->dqrr.dqrr_size - 1); + if (irq_threshold >= p->dqrr.dqrr_size) { + pr_err("irq_threshold must be < %u\n", p->dqrr.dqrr_size - 1); return -EINVAL; }