Re: [dpdk-dev] [PATCH 6/6] eal: Fix interface of pci_map_resource()

["Iremonger, Bernard" <bernard.iremonger@intel.com>]

> -----Original Message-----
> From: Tetsuya Mukawa [mailto:mukawa@igel.co.jp]
> Sent: Tuesday, March 17, 2015 9:31 AM
> To: dev@dpdk.org
> Cc: Iremonger, Bernard; Richardson, Bruce; Tetsuya Mukawa
> Subject: [PATCH 6/6] eal: Fix interface of pci_map_resource()
> 
> The function is implemented in both linuxapp and bsdapp, but interface is different. The patch fixes
> the function of bsdapp to do same as linuxapp. After applying it, file descriptor should be opened and
> closed out of pci_map_resource().
> Also, remove redundant error messages from linuxapp.
> 
> Signed-off-by: Tetsuya Mukawa <mukawa@igel.co.jp>
> ---
>  lib/librte_eal/bsdapp/eal/eal_pci.c       | 109 ++++++++++++++++++------------
>  lib/librte_eal/linuxapp/eal/eal_pci_uio.c |  21 +++---
>  2 files changed, 75 insertions(+), 55 deletions(-)
> 
> diff --git a/lib/librte_eal/bsdapp/eal/eal_pci.c b/lib/librte_eal/bsdapp/eal/eal_pci.c
> index 08b91b4..21a3d79 100644
> --- a/lib/librte_eal/bsdapp/eal/eal_pci.c
> +++ b/lib/librte_eal/bsdapp/eal/eal_pci.c
> @@ -100,7 +100,7 @@ struct mapped_pci_resource {
> 
>  	struct rte_pci_addr pci_addr;
>  	char path[PATH_MAX];
> -	size_t nb_maps;
> +	int nb_maps;
>  	struct pci_map maps[PCI_MAX_RESOURCE];  };
> 
> @@ -122,47 +122,30 @@ pci_unbind_kernel_driver(struct rte_pci_device *dev __rte_unused)
> 
>  /* map a particular resource from a file */  static void * -pci_map_resource(void *requested_addr,
> const char *devname, off_t offset,
> -		 size_t size)
> +pci_map_resource(void *requested_addr, int fd, off_t offset, size_t size,
> +		 int additional_flags)
>  {
> -	int fd;
>  	void *mapaddr;
> 
> -	/*
> -	 * open devname, to mmap it
> -	 */
> -	fd = open(devname, O_RDWR);
> -	if (fd < 0) {
> -		RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
> -			devname, strerror(errno));
> -		goto fail;
> -	}
> -
>  	/* Map the PCI memory resource of device */
>  	mapaddr = mmap(requested_addr, size, PROT_READ | PROT_WRITE,
> -			MAP_SHARED, fd, offset);
> -	close(fd);
> -	if (mapaddr == MAP_FAILED ||
> -			(requested_addr != NULL && mapaddr != requested_addr)) {
> -		RTE_LOG(ERR, EAL, "%s(): cannot mmap(%s(%d), %p, 0x%lx, 0x%lx):"
> -			" %s (%p)\n", __func__, devname, fd, requested_addr,
> +			MAP_SHARED | additional_flags, fd, offset);
> +	if (mapaddr == MAP_FAILED) {
> +		RTE_LOG(ERR, EAL,
> +			"%s(): cannot mmap(%d, %p, 0x%lx, 0x%lx): %s (%p)\n",
> +			__func__, fd, requested_addr,
>  			(unsigned long)size, (unsigned long)offset,
>  			strerror(errno), mapaddr);
> -		goto fail;

Hi Tetsuya,

Previously pci_map_resource() returned NULL  when MAP_FAILED occurred.
It now returns MAP_FAILED.
Where pci_map_resource() is called it should now check for MAP_FAILED instead of NULL, or else the return value of NULL should be restored.
There is another comment below.


> -	}
> -
> -	RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n", mapaddr);
> +	} else
> +		RTE_LOG(DEBUG, EAL, "  PCI memory mapped at %p\n", mapaddr);
> 
>  	return mapaddr;
> -
> -fail:
> -	return NULL;
>  }
> 
>  static int
>  pci_uio_map_secondary(struct rte_pci_device *dev)  {
> -	size_t i;
> +	int i, fd;
>  	struct mapped_pci_resource *uio_res;
>  	struct mapped_pci_res_list *uio_res_list =
>  			RTE_TAILQ_CAST(rte_uio_tailq.head, mapped_pci_res_list); @@ -170,19
> +153,34 @@ pci_uio_map_secondary(struct rte_pci_device *dev)
>  	TAILQ_FOREACH(uio_res, uio_res_list, next) {
> 
>  		/* skip this element if it doesn't match our PCI address */
> -		if (memcmp(&uio_res->pci_addr, &dev->addr, sizeof(dev->addr)))
> +		if (rte_eal_compare_pci_addr(&uio_res->pci_addr, &dev->addr))
>  			continue;
> 
>  		for (i = 0; i != uio_res->nb_maps; i++) {
> -			if (pci_map_resource(uio_res->maps[i].addr,
> -					     uio_res->path,
> -					     (off_t)uio_res->maps[i].offset,
> -					     (size_t)uio_res->maps[i].size)
> -			    != uio_res->maps[i].addr) {
> +			/*
> +			 * open devname, to mmap it
> +			 */
> +			fd = open(uio_res->maps[i].path, O_RDWR);
> +			if (fd < 0) {
> +				RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
> +					uio_res->maps[i].path, strerror(errno));
> +				return -1;
> +			}
> +
> +			void *mapaddr = pci_map_resource(uio_res->maps[i].addr,
> +					fd, (off_t)uio_res->maps[i].offset,
> +					(size_t)uio_res->maps[i].size, 0);
> +			if (mapaddr != uio_res->maps[i].addr) {
>  				RTE_LOG(ERR, EAL,
> -					"Cannot mmap device resource\n");
> +						"Cannot mmap device resource "
> +						"file %s to address: %p\n",
> +						uio_res->maps[i].path,
> +						uio_res->maps[i].addr);
> +				close(fd);
>  				return -1;
>  			}
> +			/* fd is not needed in slave process, close it */
> +			close(fd);
>  		}
>  		return 0;
>  	}
> @@ -248,24 +246,43 @@ pci_uio_map_resource(struct rte_pci_device *dev)
> 
>  	maps = uio_res->maps;
>  	for (i = 0, map_idx = 0; i != PCI_MAX_RESOURCE; i++) {
> +		int fd;
> 
>  		/* skip empty BAR */
>  		if ((phaddr = dev->mem_resource[i].phys_addr) == 0)
>  			continue;
> 
> +		/* allocate memory to keep path */
> +		maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
> +		if (maps[map_idx].path == NULL) {
> +			RTE_LOG(ERR, EAL, "Cannot allocate memory for "
> +					"path: %s\n", strerror(errno));
> +			goto fail0;
> +		}
> +
> +		/*
> +		 * open resource file, to mmap it
> +		 */
> +		fd = open(devname, O_RDWR);
> +		if (fd < 0) {
> +			RTE_LOG(ERR, EAL, "Cannot open %s: %s\n",
> +					devname, strerror(errno));
> +			goto fail1;
> +		}
> +
>  		/* if matching map is found, then use it */
>  		offset = i * pagesz;
> -		maps[map_idx].offset = offset;
> +		mapaddr = pci_map_resource(NULL, fd, (off_t)offset,
> +					(size_t)dev->mem_resource[i].len, 0);
> +		close(fd);
> +		if (mapaddr == NULL)

The check here should be for MAP_FAILED instead of NULL.

Regards,
Bernard.


> +			goto fail1;
> +
>  		maps[map_idx].phaddr = dev->mem_resource[i].phys_addr;
>  		maps[map_idx].size = dev->mem_resource[i].len;
> -		mapaddr = pci_map_resource(NULL, devname, (off_t)offset,
> -					(size_t)maps[map_idx].size);
> -		if ((maps[map_idx].addr != NULL) || (mapaddr == NULL)) {
> -			rte_free(uio_res);
> -			return -1;
> -		}
> -
>  		maps[map_idx].addr = mapaddr;
> +		maps[map_idx].offset = offset;
> +		strcpy(maps[map_idx].path, devname);
>  		map_idx++;
>  		dev->mem_resource[i].addr = mapaddr;
>  	}
> @@ -275,6 +292,12 @@ pci_uio_map_resource(struct rte_pci_device *dev)
>  	TAILQ_INSERT_TAIL(uio_res_list, uio_res, next);
> 
>  	return 0;
> +
> +fail1:
> +	rte_free(maps[map_idx].path);
> +fail0:
> +	rte_free(uio_res);
> +	return -1;
>  }
> 
>  /* Scan one pci sysfs entry, and fill the devices list from it. */ diff --git
> a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> index 5044884..9eeaebb 100644
> --- a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> +++ b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
> @@ -116,17 +116,11 @@ pci_uio_map_secondary(struct rte_pci_device *dev)
>  					fd, (off_t)uio_res->maps[i].offset,
>  					(size_t)uio_res->maps[i].size, 0);
>  			if (mapaddr != uio_res->maps[i].addr) {
> -				if (mapaddr == MAP_FAILED)
> -					RTE_LOG(ERR, EAL,
> -							"Cannot mmap device resource file %s: %s\n",
> -							uio_res->maps[i].path,
> -							strerror(errno));
> -				else
> -					RTE_LOG(ERR, EAL,
> -							"Cannot mmap device resource file %s to
> address: %p\n",
> -							uio_res->maps[i].path,
> -							uio_res->maps[i].addr);
> -
> +				RTE_LOG(ERR, EAL,
> +						"Cannot mmap device resource "
> +						"file %s to address: %p\n",
> +						uio_res->maps[i].path,
> +						uio_res->maps[i].addr);
>  				close(fd);
>  				return -1;
>  			}
> @@ -348,8 +342,11 @@ pci_uio_map_resource(struct rte_pci_device *dev)
> 
>  		/* allocate memory to keep path */
>  		maps[map_idx].path = rte_malloc(NULL, strlen(devname) + 1, 0);
> -		if (maps[map_idx].path == NULL)
> +		if (maps[map_idx].path == NULL) {
> +			RTE_LOG(ERR, EAL, "Cannot allocate memory for "
> +					"path: %s\n", strerror(errno));
>  			goto fail0;
> +		}
> 
>  		/*
>  		 * open resource file, to mmap it
> --
> 1.9.1