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dkim=pass header.d=deltatee.com header.s=20200525 header.b=eGbHnD9C; spf=pass (imf10.hostedemail.com: domain of gunthorp@deltatee.com designates 204.191.154.188 as permitted sender) smtp.mailfrom=gunthorp@deltatee.com; dmarc=none X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 18E1640002D1 X-Stat-Signature: efmikgoibe4dby8aud6xo8w5f5fp3h8y X-HE-Tag: 1620945139-597553 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: In order to call the calc_map_type_and_dist_warn() function from a dma_map operation, the function must not sleep. The only reason it sleeps is to allocate memory for the seq_buf to print a verbose warning telling the user how to disable ACS for that path. Instead of allocating the memory with kmalloc, allocate it on the stack with a smaller buffer. A 128B buffer is enough to print 10 pci device names. A system with 10 bridge ports between two devices that have ACS enabled would be unusually large, so this should still be a reasonable limit. This also allows cleaning up the awkward (and broken) return with -ENOMEM which contradicts the return type and the caller was not prepared for. Signed-off-by: Logan Gunthorpe --- drivers/pci/p2pdma.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c index 6f90e9812f6e..3a5fb63c5f2c 100644 --- a/drivers/pci/p2pdma.c +++ b/drivers/pci/p2pdma.c @@ -500,11 +500,10 @@ calc_map_type_and_dist_warn(struct pci_dev *provider, struct pci_dev *client, { struct seq_buf acs_list; bool acs_redirects; + char buf[128]; int ret; - seq_buf_init(&acs_list, kmalloc(PAGE_SIZE, GFP_KERNEL), PAGE_SIZE); - if (!acs_list.buffer) - return -ENOMEM; + seq_buf_init(&acs_list, buf, sizeof(buf)); ret = calc_map_type_and_dist(provider, client, dist, &acs_redirects, &acs_list); @@ -522,8 +521,6 @@ calc_map_type_and_dist_warn(struct pci_dev *provider, struct pci_dev *client, pci_name(provider)); } - kfree(acs_list.buffer); - return ret; }