[PATCH][linux-next] soc: fsl: dpio: Unsigned compared against 0 in qbman_swp_set_irq_coalescing()

[Tim Gardner]

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")

Cc: Roy Pledge <roy.ple...@nxp.com>
Cc: Li Yang <leoyang...@nxp.com>
Cc: linux-ker...@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-arm-ker...@lists.infradead.org
Signed-off-by: Tim Gardner <tim.gard...@canonical.com>
---

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.

---
 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;
-- 
2.33.1