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Commit 92dc6895 authored by Christoph Hellwig's avatar Christoph Hellwig
Browse files

nvme-pci: fix host memory buffer allocation fallback 



nvme_alloc_host_mem currently contains two loops that are interwinded,
and the outer retry loop turns out to be broken.  Fix this by untangling
the two.

Based on a report an initial patch from Akinobu Mita.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reported-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Tested-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: default avatarKeith Busch <keith.busch@intel.com>
Cc: stable@vger.kernel.org
parent 608cc4b1

drivers/nvme/host/pci.c

+30 −18
Original line number Diff line number Diff line
@@ -1612,18 +1612,16 @@ static void nvme_free_host_mem(struct nvme_dev *dev) 
	dev->host_mem_descs = NULL;

}



static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)

static int __nvme_alloc_host_mem(struct nvme_dev *dev, u64 preferred,

		u32 chunk_size)

{

	struct nvme_host_mem_buf_desc *descs;

	u32 chunk_size, max_entries, len;

	u32 max_entries, len;

	dma_addr_t descs_dma;

	int i = 0;

	void **bufs;

	u64 size = 0, tmp;



	/* start big and work our way down */

	chunk_size = min(preferred, (u64)PAGE_SIZE << MAX_ORDER);

retry:

	tmp = (preferred + chunk_size - 1);

	do_div(tmp, chunk_size);

	max_entries = tmp;
@@ -1650,15 +1648,9 @@ static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred) 
		i++;

	}



	if (!size || (min && size < min)) {

		dev_warn(dev->ctrl.device,

			"failed to allocate host memory buffer.\n");

	if (!size)

		goto out_free_bufs;

	}



	dev_info(dev->ctrl.device,

		"allocated %lld MiB host memory buffer.\n",

		size >> ilog2(SZ_1M));

	dev->nr_host_mem_descs = i;

	dev->host_mem_size = size;

	dev->host_mem_descs = descs;
@@ -1679,15 +1671,28 @@ static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred) 
	dma_free_coherent(dev->dev, max_entries * sizeof(*descs), descs,

			descs_dma);

out:

	/* try a smaller chunk size if we failed early */

	if (chunk_size >= PAGE_SIZE * 2 && (i == 0 || size < min)) {

		chunk_size /= 2;

		goto retry;

	}

	dev->host_mem_descs = NULL;

	return -ENOMEM;

}



static int nvme_alloc_host_mem(struct nvme_dev *dev, u64 min, u64 preferred)

{

	u32 chunk_size;



	/* start big and work our way down */

	for (chunk_size = min_t(u64, preferred, PAGE_SIZE << MAX_ORDER);

	     chunk_size >= PAGE_SIZE * 2;

	     chunk_size /= 2) {

		if (!__nvme_alloc_host_mem(dev, preferred, chunk_size)) {

			if (!min || dev->host_mem_size >= min)

				return 0;

			nvme_free_host_mem(dev);

		}

	}



	return -ENOMEM;

}



static void nvme_setup_host_mem(struct nvme_dev *dev)

{

	u64 max = (u64)max_host_mem_size_mb * SZ_1M;
@@ -1715,10 +1720,17 @@ static void nvme_setup_host_mem(struct nvme_dev *dev) 
	}



	if (!dev->host_mem_descs) {

		if (nvme_alloc_host_mem(dev, min, preferred))

		if (nvme_alloc_host_mem(dev, min, preferred)) {

			dev_warn(dev->ctrl.device,

				"failed to allocate host memory buffer.\n");

			return;

		}



		dev_info(dev->ctrl.device,

			"allocated %lld MiB host memory buffer.\n",

			dev->host_mem_size >> ilog2(SZ_1M));

	}



	if (nvme_set_host_mem(dev, enable_bits))

		nvme_free_host_mem(dev);

}