Hi, On 2021/07/27 13:05, Kunihiko Hayashi wrote:
Hi Dan, Thank you for reporting. On 2021/07/26 16:34, Dan Carpenter wrote:Hello Kunihiko Hayashi, The patch 667b9251440b: "dmaengine: uniphier-xdmac: Add UniPhier external DMA controller driver" from Feb 21, 2020, leads to the following static checker warning: drivers/dma/uniphier-xdmac.c:212 uniphier_xdmac_chan_stop() warn: sleeping in atomic context drivers/dma/uniphier-xdmac.c 197 static int uniphier_xdmac_chan_stop(struct uniphier_xdmac_chan *xc) 198 { 199 u32 val; 200 201 /* disable interrupt */ 202 val = readl(xc->reg_ch_base + XDMAC_IEN); 203 val &= ~(XDMAC_IEN_ENDIEN | XDMAC_IEN_ERRIEN); 204 writel(val, xc->reg_ch_base + XDMAC_IEN); 205 206 /* stop XDMAC */ 207 val = readl(xc->reg_ch_base + XDMAC_TSS); 208 val &= ~XDMAC_TSS_REQ; 209 writel(0, xc->reg_ch_base + XDMAC_TSS); 210 211 /* wait until transfer is stopped */ --> 212 return readl_poll_timeout(xc->reg_ch_base + XDMAC_STAT, val, 213 !(val & XDMAC_STAT_TENF), 100, 1000); ^^^ This is doing a 100 us sleep but both callers hold a spin lock.Yes, this waiting code is in spin lock context. I think that the function needs to be rewritten in tasklet.
I found this can be simply replaced with readl_poll_timeout_atomic(). I'll fix it. Thank you, --- Best Regards Kunihiko Hayashi
