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Commit e64aa657 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Doug Ledford
Browse files

target: enhance and export target_alloc_sgl/target_free_sgl 



The SRP target driver will need to allocate and chain it's own SGLs soon.
For this export target_alloc_sgl, and add a new argument to it so that it
can allocate an additional chain entry that doesn't point to a page.  Also
export transport_free_sgl after renaming it to target_free_sgl to free
these SGLs again.

Signed-off-by: default avatarChristoph Hellwig <hch@lst.de>
Reviewed-by: default avatarBart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
parent a060b562

drivers/target/target_core_transport.c

+18 −14
Original line number Diff line number Diff line
@@ -2195,7 +2195,7 @@ static void target_complete_ok_work(struct work_struct *work) 
	transport_handle_queue_full(cmd, cmd->se_dev);

}



static inline void transport_free_sgl(struct scatterlist *sgl, int nents)

void target_free_sgl(struct scatterlist *sgl, int nents)

{

	struct scatterlist *sg;

	int count;
@@ -2205,6 +2205,7 @@ static inline void transport_free_sgl(struct scatterlist *sgl, int nents) 


	kfree(sgl);

}

EXPORT_SYMBOL(target_free_sgl);



static inline void transport_reset_sgl_orig(struct se_cmd *cmd)

{
@@ -2225,7 +2226,7 @@ static inline void transport_reset_sgl_orig(struct se_cmd *cmd) 
static inline void transport_free_pages(struct se_cmd *cmd)

{

	if (!(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {

		transport_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);

		target_free_sgl(cmd->t_prot_sg, cmd->t_prot_nents);

		cmd->t_prot_sg = NULL;

		cmd->t_prot_nents = 0;

	}
@@ -2236,7 +2237,7 @@ static inline void transport_free_pages(struct se_cmd *cmd) 
		 * SG_TO_MEM_NOALLOC to function with COMPARE_AND_WRITE

		 */

		if (cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) {

			transport_free_sgl(cmd->t_bidi_data_sg,

			target_free_sgl(cmd->t_bidi_data_sg,

					   cmd->t_bidi_data_nents);

			cmd->t_bidi_data_sg = NULL;

			cmd->t_bidi_data_nents = 0;
@@ -2246,11 +2247,11 @@ static inline void transport_free_pages(struct se_cmd *cmd) 
	}

	transport_reset_sgl_orig(cmd);



	transport_free_sgl(cmd->t_data_sg, cmd->t_data_nents);

	target_free_sgl(cmd->t_data_sg, cmd->t_data_nents);

	cmd->t_data_sg = NULL;

	cmd->t_data_nents = 0;



	transport_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);

	target_free_sgl(cmd->t_bidi_data_sg, cmd->t_bidi_data_nents);

	cmd->t_bidi_data_sg = NULL;

	cmd->t_bidi_data_nents = 0;

}
@@ -2324,20 +2325,22 @@ EXPORT_SYMBOL(transport_kunmap_data_sg); 


int

target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length,

		 bool zero_page)

		 bool zero_page, bool chainable)

{

	struct scatterlist *sg;

	struct page *page;

	gfp_t zero_flag = (zero_page) ? __GFP_ZERO : 0;

	unsigned int nent;

	unsigned int nalloc, nent;

	int i = 0;



	nent = DIV_ROUND_UP(length, PAGE_SIZE);

	sg = kmalloc(sizeof(struct scatterlist) * nent, GFP_KERNEL);

	nalloc = nent = DIV_ROUND_UP(length, PAGE_SIZE);

	if (chainable)

		nalloc++;

	sg = kmalloc_array(nalloc, sizeof(struct scatterlist), GFP_KERNEL);

	if (!sg)

		return -ENOMEM;



	sg_init_table(sg, nent);

	sg_init_table(sg, nalloc);



	while (length) {

		u32 page_len = min_t(u32, length, PAGE_SIZE);
@@ -2361,6 +2364,7 @@ target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents, u32 length, 
	kfree(sg);

	return -ENOMEM;

}

EXPORT_SYMBOL(target_alloc_sgl);



/*

 * Allocate any required resources to execute the command.  For writes we
@@ -2376,7 +2380,7 @@ transport_generic_new_cmd(struct se_cmd *cmd) 
	if (cmd->prot_op != TARGET_PROT_NORMAL &&

	    !(cmd->se_cmd_flags & SCF_PASSTHROUGH_PROT_SG_TO_MEM_NOALLOC)) {

		ret = target_alloc_sgl(&cmd->t_prot_sg, &cmd->t_prot_nents,

				       cmd->prot_length, true);

				       cmd->prot_length, true, false);

		if (ret < 0)

			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	}
@@ -2401,13 +2405,13 @@ transport_generic_new_cmd(struct se_cmd *cmd) 


			ret = target_alloc_sgl(&cmd->t_bidi_data_sg,

					       &cmd->t_bidi_data_nents,

					       bidi_length, zero_flag);

					       bidi_length, zero_flag, false);

			if (ret < 0)

				return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

		}



		ret = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,

				       cmd->data_length, zero_flag);

				       cmd->data_length, zero_flag, false);

		if (ret < 0)

			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	} else if ((cmd->se_cmd_flags & SCF_COMPARE_AND_WRITE) &&
@@ -2421,7 +2425,7 @@ transport_generic_new_cmd(struct se_cmd *cmd) 


		ret = target_alloc_sgl(&cmd->t_bidi_data_sg,

				       &cmd->t_bidi_data_nents,

				       caw_length, zero_flag);

				       caw_length, zero_flag, false);

		if (ret < 0)

			return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	}

drivers/target/target_core_xcopy.c

+1 −1
Original line number Diff line number Diff line
@@ -563,7 +563,7 @@ static int target_xcopy_setup_pt_cmd( 


	if (alloc_mem) {

		rc = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,

				      cmd->data_length, false);

				      cmd->data_length, false, false);

		if (rc < 0) {

			ret = rc;

			goto out;

include/target/target_core_backend.h

+0 −1
Original line number Diff line number Diff line
@@ -85,7 +85,6 @@ extern struct configfs_attribute *passthrough_attrib_attrs[]; 
void	*transport_kmap_data_sg(struct se_cmd *);

void	transport_kunmap_data_sg(struct se_cmd *);

/* core helpers also used by xcopy during internal command setup */

int	target_alloc_sgl(struct scatterlist **, unsigned int *, u32, bool);

sense_reason_t	transport_generic_map_mem_to_cmd(struct se_cmd *,

		struct scatterlist *, u32, struct scatterlist *, u32);

include/target/target_core_fabric.h

+4 −0
Original line number Diff line number Diff line
@@ -185,6 +185,10 @@ int core_tpg_set_initiator_node_tag(struct se_portal_group *, 
int	core_tpg_register(struct se_wwn *, struct se_portal_group *, int);

int	core_tpg_deregister(struct se_portal_group *);



int	target_alloc_sgl(struct scatterlist **sgl, unsigned int *nents,

		u32 length, bool zero_page, bool chainable);

void	target_free_sgl(struct scatterlist *sgl, int nents);



/*

 * The LIO target core uses DMA_TO_DEVICE to mean that data is going

 * to the target (eg handling a WRITE) and DMA_FROM_DEVICE to mean