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Commit cfc57a18 authored by Jordan Crouse's avatar Jordan Crouse Committed by Rob Clark
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drm: drm_printer: Add printer for devcoredump 



Add a drm printer suitable for use with the read callback for
devcoredump or other suitable buffer based output format that
isn't otherwise covered by seq_file.

v2: Add improved documentation per Daniel Vetter

Signed-off-by: default avatarJordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: default avatarRob Clark <robdclark@gmail.com>
parent 489cae63

drivers/gpu/drm/drm_print.c

+74 −0
Original line number Diff line number Diff line
@@ -30,6 +30,80 @@ 
#include <drm/drmP.h>

#include <drm/drm_print.h>



void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf)

{

	struct drm_print_iterator *iterator = p->arg;

	ssize_t len;



	if (!iterator->remain)

		return;



	/* Figure out how big the string will be */

	len = snprintf(NULL, 0, "%pV", vaf);



	if (iterator->offset < iterator->start) {

		char *buf;

		ssize_t copy;



		if (iterator->offset + len <= iterator->start) {

			iterator->offset += len;

			return;

		}



		/* Print the string into a temporary buffer */

		buf = kmalloc(len + 1,

			GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);

		if (!buf)

			return;



		snprintf(buf, len + 1, "%pV", vaf);



		copy = len - (iterator->start - iterator->offset);



		if (copy > iterator->remain)

			copy = iterator->remain;



		/* Copy out the bit of the string that we need */

		memcpy(iterator->data,

			buf + (iterator->start - iterator->offset), copy);



		iterator->offset = iterator->start + copy;

		iterator->remain -= copy;



		kfree(buf);

	} else {

		char *buf;

		ssize_t pos = iterator->offset - iterator->start;



		if (len < iterator->remain) {

			snprintf(((char *) iterator->data) + pos,

				iterator->remain, "%pV", vaf);



			iterator->offset += len;

			iterator->remain -= len;



			return;

		}



		/* Print the string into a temporary buffer */

		buf = kmalloc(len + 1,

			GFP_KERNEL | __GFP_NOWARN | __GFP_NORETRY);

		if (!buf)

			return;



		snprintf(buf, len + 1, "%pV", vaf);



		/* Copy out the remaining bits */

		memcpy(iterator->data + pos, buf, iterator->remain);



		iterator->offset += iterator->remain;

		iterator->remain = 0;



		kfree(buf);

	}

}

EXPORT_SYMBOL(__drm_printfn_coredump);



void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf)

{

	seq_printf(p->arg, "%pV", vaf);

include/drm/drm_print.h

+65 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ struct drm_printer { 
	const char *prefix;

};



void __drm_printfn_coredump(struct drm_printer *p, struct va_format *vaf);

void __drm_printfn_seq_file(struct drm_printer *p, struct va_format *vaf);

void __drm_printfn_info(struct drm_printer *p, struct va_format *vaf);

void __drm_printfn_debug(struct drm_printer *p, struct va_format *vaf);
@@ -104,6 +105,70 @@ drm_vprintf(struct drm_printer *p, const char *fmt, va_list *va) 
#define drm_printf_indent(printer, indent, fmt, ...) \

	drm_printf((printer), "%.*s" fmt, (indent), "\t\t\t\t\tX", ##__VA_ARGS__)



/**

 * struct drm_print_iterator - local struct used with drm_printer_coredump

 * @data: Pointer to the devcoredump output buffer

 * @start: The offset within the buffer to start writing

 * @remain: The number of bytes to write for this iteration

 */

struct drm_print_iterator {

	void *data;

	ssize_t start;

	ssize_t remain;

	/* private: */

	ssize_t offset;

};



/**

 * drm_coredump_printer - construct a &drm_printer that can output to a buffer

 * from the read function for devcoredump

 * @iter: A pointer to a struct drm_print_iterator for the read instance

 *

 * This wrapper extends drm_printf() to work with a dev_coredumpm() callback

 * function. The passed in drm_print_iterator struct contains the buffer

 * pointer, size and offset as passed in from devcoredump.

 *

 * For example::

 *

 *	void coredump_read(char *buffer, loff_t offset, size_t count,

 *		void *data, size_t datalen)

 *	{

 *		struct drm_print_iterator iter;

 *		struct drm_printer p;

 *

 *		iter.data = buffer;

 *		iter.start = offset;

 *		iter.remain = count;

 *

 *		p = drm_coredump_printer(&iter);

 *

 *		drm_printf(p, "foo=%d\n", foo);

 *	}

 *

 *	void makecoredump(...)

 *	{

 *		...

 *		dev_coredumpm(dev, THIS_MODULE, data, 0, GFP_KERNEL,

 *			coredump_read, ...)

 *	}

 *

 * RETURNS:

 * The &drm_printer object

 */

static inline struct drm_printer

drm_coredump_printer(struct drm_print_iterator *iter)

{

	struct drm_printer p = {

		.printfn = __drm_printfn_coredump,

		.arg = iter,

	};



	/* Set the internal offset of the iterator to zero */

	iter->offset = 0;



	return p;

}



/**

 * drm_seq_file_printer - construct a &drm_printer that outputs to &seq_file

 * @f:  the &struct seq_file to output to