X-Git-Url: https://git.libre-soc.org/?a=blobdiff_plain;f=src%2Fgallium%2Fdrivers%2Fsvga%2Fsvga_resource_buffer_upload.c;h=3fc14f83c11d3a5d9415dec16c7ba8cf9b72b54f;hb=d5b1731178378b3d828c74368f6bfe85edc10618;hp=acef60f46472d12197955f2848e9c439f728e371;hpb=6fc532ae05352a5540c658580cde08b1e0e9f84c;p=mesa.git diff --git a/src/gallium/drivers/svga/svga_resource_buffer_upload.c b/src/gallium/drivers/svga/svga_resource_buffer_upload.c index acef60f4647..3fc14f83c11 100644 --- a/src/gallium/drivers/svga/svga_resource_buffer_upload.c +++ b/src/gallium/drivers/svga/svga_resource_buffer_upload.c @@ -23,51 +23,75 @@ * **********************************************************/ -#include "svga_cmd.h" +#include "os/os_thread.h" #include "pipe/p_state.h" #include "pipe/p_defines.h" #include "util/u_inlines.h" -#include "os/os_thread.h" #include "util/u_math.h" #include "util/u_memory.h" +#include "util/u_double_list.h" +#include "svga_cmd.h" #include "svga_context.h" -#include "svga_screen.h" +#include "svga_debug.h" #include "svga_resource_buffer.h" #include "svga_resource_buffer_upload.h" +#include "svga_screen.h" #include "svga_winsys.h" -#include "svga_debug.h" +/** + * Describes a complete SVGA_3D_CMD_UPDATE_GB_IMAGE command + * + */ +struct svga_3d_update_gb_image { + SVGA3dCmdHeader header; + SVGA3dCmdUpdateGBImage body; +}; + +struct svga_3d_invalidate_gb_image { + SVGA3dCmdHeader header; + SVGA3dCmdInvalidateGBImage body; +}; -/* Allocate a winsys_buffer (ie. DMA, aka GMR memory). + +/** + * Allocate a winsys_buffer (ie. DMA, aka GMR memory). + * + * It will flush and retry in case the first attempt to create a DMA buffer + * fails, so it should not be called from any function involved in flushing + * to avoid recursion. */ struct svga_winsys_buffer * -svga_winsys_buffer_create( struct svga_screen *ss, - unsigned alignment, +svga_winsys_buffer_create( struct svga_context *svga, + unsigned alignment, unsigned usage, unsigned size ) { - struct svga_winsys_screen *sws = ss->sws; + struct svga_screen *svgascreen = svga_screen(svga->pipe.screen); + struct svga_winsys_screen *sws = svgascreen->sws; struct svga_winsys_buffer *buf; - + /* Just try */ buf = sws->buffer_create(sws, alignment, usage, size); - if(!buf) { + if (!buf) { + SVGA_DBG(DEBUG_DMA|DEBUG_PERF, "flushing context to find %d bytes GMR\n", + size); - SVGA_DBG(DEBUG_DMA|DEBUG_PERF, "flushing screen to find %d bytes GMR\n", - size); - /* Try flushing all pending DMAs */ - svga_screen_flush(ss, NULL); + svga_context_flush(svga, NULL); buf = sws->buffer_create(sws, alignment, usage, size); - } - + return buf; } +/** + * Destroy HW storage if separate from the host surface. + * In the GB case, the HW storage is associated with the host surface + * and is therefore a No-op. + */ void svga_buffer_destroy_hw_storage(struct svga_screen *ss, struct svga_buffer *sbuf) { @@ -75,7 +99,7 @@ svga_buffer_destroy_hw_storage(struct svga_screen *ss, struct svga_buffer *sbuf) assert(!sbuf->map.count); assert(sbuf->hwbuf); - if(sbuf->hwbuf) { + if (sbuf->hwbuf) { sws->buffer_destroy(sws, sbuf->hwbuf); sbuf->hwbuf = NULL; } @@ -84,8 +108,8 @@ svga_buffer_destroy_hw_storage(struct svga_screen *ss, struct svga_buffer *sbuf) /** - * Allocate DMA'ble storage for the buffer. - * + * Allocate DMA'ble or Updatable storage for the buffer. + * * Called before mapping a buffer. */ enum pipe_error @@ -94,18 +118,23 @@ svga_buffer_create_hw_storage(struct svga_screen *ss, { assert(!sbuf->user); - if(!sbuf->hwbuf) { + if (ss->sws->have_gb_objects) { + assert(sbuf->handle || !sbuf->dma.pending); + return svga_buffer_create_host_surface(ss, sbuf); + } + if (!sbuf->hwbuf) { + struct svga_winsys_screen *sws = ss->sws; unsigned alignment = 16; unsigned usage = 0; unsigned size = sbuf->b.b.width0; - - sbuf->hwbuf = svga_winsys_buffer_create(ss, alignment, usage, size); - if(!sbuf->hwbuf) + + sbuf->hwbuf = sws->buffer_create(sws, alignment, usage, size); + if (!sbuf->hwbuf) return PIPE_ERROR_OUT_OF_MEMORY; - + assert(!sbuf->dma.pending); } - + return PIPE_OK; } @@ -115,29 +144,31 @@ enum pipe_error svga_buffer_create_host_surface(struct svga_screen *ss, struct svga_buffer *sbuf) { - if(!sbuf->handle) { + assert(!sbuf->user); + + if (!sbuf->handle) { sbuf->key.flags = 0; - + sbuf->key.format = SVGA3D_BUFFER; - if(sbuf->b.b.bind & PIPE_BIND_VERTEX_BUFFER) + if (sbuf->b.b.bind & PIPE_BIND_VERTEX_BUFFER) sbuf->key.flags |= SVGA3D_SURFACE_HINT_VERTEXBUFFER; - if(sbuf->b.b.bind & PIPE_BIND_INDEX_BUFFER) + if (sbuf->b.b.bind & PIPE_BIND_INDEX_BUFFER) sbuf->key.flags |= SVGA3D_SURFACE_HINT_INDEXBUFFER; - + sbuf->key.size.width = sbuf->b.b.width0; sbuf->key.size.height = 1; sbuf->key.size.depth = 1; - + sbuf->key.numFaces = 1; sbuf->key.numMipLevels = 1; sbuf->key.cachable = 1; - + SVGA_DBG(DEBUG_DMA, "surface_create for buffer sz %d\n", sbuf->b.b.width0); sbuf->handle = svga_screen_surface_create(ss, &sbuf->key); - if(!sbuf->handle) + if (!sbuf->handle) return PIPE_ERROR_OUT_OF_MEMORY; - + /* Always set the discard flag on the first time the buffer is written * as svga_screen_surface_create might have passed a recycled host * buffer. @@ -146,20 +177,118 @@ svga_buffer_create_host_surface(struct svga_screen *ss, SVGA_DBG(DEBUG_DMA, " --> got sid %p sz %d (buffer)\n", sbuf->handle, sbuf->b.b.width0); } - + return PIPE_OK; -} +} void svga_buffer_destroy_host_surface(struct svga_screen *ss, struct svga_buffer *sbuf) { - if(sbuf->handle) { + if (sbuf->handle) { SVGA_DBG(DEBUG_DMA, " ungrab sid %p sz %d\n", sbuf->handle, sbuf->b.b.width0); svga_screen_surface_destroy(ss, &sbuf->key, &sbuf->handle); } -} +} + + +/** + * Insert a number of preliminary UPDATE_GB_IMAGE commands in the + * command buffer, equal to the current number of mapped ranges. + * The UPDATE_GB_IMAGE commands will be patched with the + * actual ranges just before flush. + */ +static enum pipe_error +svga_buffer_upload_gb_command(struct svga_context *svga, + struct svga_buffer *sbuf) +{ + struct svga_winsys_context *swc = svga->swc; + SVGA3dCmdUpdateGBImage *cmd; + struct svga_3d_update_gb_image *ccmd = NULL; + uint32 numBoxes = sbuf->map.num_ranges; + struct pipe_resource *dummy; + unsigned int i; + + assert(numBoxes); + assert(sbuf->dma.updates == NULL); + + if (sbuf->dma.flags.discard) { + struct svga_3d_invalidate_gb_image *cicmd = NULL; + SVGA3dCmdInvalidateGBImage *icmd; + + /* Allocate FIFO space for one INVALIDATE_GB_IMAGE command followed by + * 'numBoxes' UPDATE_GB_IMAGE commands. Allocate all at once rather + * than with separate commands because we need to properly deal with + * filling the command buffer. + */ + icmd = SVGA3D_FIFOReserve(swc, + SVGA_3D_CMD_INVALIDATE_GB_IMAGE, + sizeof *icmd + numBoxes * sizeof *ccmd, + 2); + if (!icmd) + return PIPE_ERROR_OUT_OF_MEMORY; + + cicmd = container_of(icmd, cicmd, body); + cicmd->header.size = sizeof *icmd; + swc->surface_relocation(swc, &icmd->image.sid, NULL, sbuf->handle, + (SVGA_RELOC_WRITE | + SVGA_RELOC_INTERNAL | + SVGA_RELOC_DMA)); + icmd->image.face = 0; + icmd->image.mipmap = 0; + + /* initialize the first UPDATE_GB_IMAGE command */ + ccmd = (struct svga_3d_update_gb_image *) &icmd[1]; + ccmd->header.id = SVGA_3D_CMD_UPDATE_GB_IMAGE; + cmd = &ccmd->body; + + } else { + /* Allocate FIFO space for 'numBoxes' UPDATE_GB_IMAGE commands */ + cmd = SVGA3D_FIFOReserve(swc, + SVGA_3D_CMD_UPDATE_GB_IMAGE, + sizeof *cmd + (numBoxes - 1) * sizeof *ccmd, + 1); + if (!cmd) + return PIPE_ERROR_OUT_OF_MEMORY; + + ccmd = container_of(cmd, ccmd, body); + } + + /* Init the first UPDATE_GB_IMAGE command */ + ccmd->header.size = sizeof *cmd; + swc->surface_relocation(swc, &cmd->image.sid, NULL, sbuf->handle, + SVGA_RELOC_WRITE | SVGA_RELOC_INTERNAL); + cmd->image.face = 0; + cmd->image.mipmap = 0; + + /* Save pointer to the first UPDATE_GB_IMAGE command so that we can + * fill in the box info below. + */ + sbuf->dma.updates = ccmd; + + /* + * Copy the relocation info, face and mipmap to all + * subsequent commands. NOTE: For winsyses that actually + * patch the image.sid member at flush time, this will fail + * miserably. For those we need to add as many relocations + * as there are copy boxes. + */ + + for (i = 1; i < numBoxes; ++i) { + memcpy(++ccmd, sbuf->dma.updates, sizeof *ccmd); + } + + /* Increment reference count */ + sbuf->dma.svga = svga; + dummy = NULL; + pipe_resource_reference(&dummy, &sbuf->b.b); + SVGA_FIFOCommitAll(swc); + + sbuf->dma.flags.discard = FALSE; + + return PIPE_OK; +} /** @@ -181,11 +310,14 @@ svga_buffer_upload_command(struct svga_context *svga, unsigned surface_flags; struct pipe_resource *dummy; - if(transfer == SVGA3D_WRITE_HOST_VRAM) { + if (svga_have_gb_objects(svga)) + return svga_buffer_upload_gb_command(svga, sbuf); + + if (transfer == SVGA3D_WRITE_HOST_VRAM) { region_flags = SVGA_RELOC_READ; surface_flags = SVGA_RELOC_WRITE; } - else if(transfer == SVGA3D_READ_HOST_VRAM) { + else if (transfer == SVGA3D_READ_HOST_VRAM) { region_flags = SVGA_RELOC_WRITE; surface_flags = SVGA_RELOC_READ; } @@ -200,13 +332,13 @@ svga_buffer_upload_command(struct svga_context *svga, SVGA_3D_CMD_SURFACE_DMA, sizeof *cmd + numBoxes * sizeof *boxes + sizeof *pSuffix, 2); - if(!cmd) + if (!cmd) return PIPE_ERROR_OUT_OF_MEMORY; swc->region_relocation(swc, &cmd->guest.ptr, guest, 0, region_flags); cmd->guest.pitch = 0; - swc->surface_relocation(swc, &cmd->host.sid, host, surface_flags); + swc->surface_relocation(swc, &cmd->host.sid, NULL, host, surface_flags); cmd->host.face = 0; cmd->host.mipmap = 0; @@ -236,67 +368,103 @@ svga_buffer_upload_command(struct svga_context *svga, * Patch up the upload DMA command reserved by svga_buffer_upload_command * with the final ranges. */ -static void +void svga_buffer_upload_flush(struct svga_context *svga, - struct svga_buffer *sbuf) + struct svga_buffer *sbuf) { - SVGA3dCopyBox *boxes; unsigned i; + struct pipe_resource *dummy; - assert(sbuf->handle); - assert(sbuf->hwbuf); + if (!sbuf->dma.pending) { + //debug_printf("no dma pending on buffer\n"); + return; + } + + assert(sbuf->handle); assert(sbuf->map.num_ranges); assert(sbuf->dma.svga == svga); - assert(sbuf->dma.boxes); - + /* - * Patch the DMA command with the final copy box. + * Patch the DMA/update command with the final copy box. */ + if (svga_have_gb_objects(svga)) { + struct svga_3d_update_gb_image *update = sbuf->dma.updates; + assert(update); - SVGA_DBG(DEBUG_DMA, "dma to sid %p\n", sbuf->handle); + for (i = 0; i < sbuf->map.num_ranges; ++i, ++update) { + SVGA3dBox *box = &update->body.box; + + SVGA_DBG(DEBUG_DMA, " bytes %u - %u\n", + sbuf->map.ranges[i].start, sbuf->map.ranges[i].end); + + box->x = sbuf->map.ranges[i].start; + box->y = 0; + box->z = 0; + box->w = sbuf->map.ranges[i].end - sbuf->map.ranges[i].start; + box->h = 1; + box->d = 1; - boxes = sbuf->dma.boxes; - for(i = 0; i < sbuf->map.num_ranges; ++i) { - SVGA_DBG(DEBUG_DMA, " bytes %u - %u\n", + assert(box->x <= sbuf->b.b.width0); + assert(box->x + box->w <= sbuf->b.b.width0); + } + } + else { + assert(sbuf->hwbuf); + assert(sbuf->dma.boxes); + SVGA_DBG(DEBUG_DMA, "dma to sid %p\n", sbuf->handle); + + for (i = 0; i < sbuf->map.num_ranges; ++i) { + SVGA3dCopyBox *box = sbuf->dma.boxes + i; + + SVGA_DBG(DEBUG_DMA, " bytes %u - %u\n", sbuf->map.ranges[i].start, sbuf->map.ranges[i].end); - boxes[i].x = sbuf->map.ranges[i].start; - boxes[i].y = 0; - boxes[i].z = 0; - boxes[i].w = sbuf->map.ranges[i].end - sbuf->map.ranges[i].start; - boxes[i].h = 1; - boxes[i].d = 1; - boxes[i].srcx = sbuf->map.ranges[i].start; - boxes[i].srcy = 0; - boxes[i].srcz = 0; + box->x = sbuf->map.ranges[i].start; + box->y = 0; + box->z = 0; + box->w = sbuf->map.ranges[i].end - sbuf->map.ranges[i].start; + box->h = 1; + box->d = 1; + box->srcx = sbuf->map.ranges[i].start; + box->srcy = 0; + box->srcz = 0; + + assert(box->x <= sbuf->b.b.width0); + assert(box->x + box->w <= sbuf->b.b.width0); + } } + /* Reset sbuf for next use/upload */ + sbuf->map.num_ranges = 0; assert(sbuf->head.prev && sbuf->head.next); - LIST_DEL(&sbuf->head); + LIST_DEL(&sbuf->head); /* remove from svga->dirty_buffers list */ #ifdef DEBUG - sbuf->head.next = sbuf->head.prev = NULL; + sbuf->head.next = sbuf->head.prev = NULL; #endif sbuf->dma.pending = FALSE; + sbuf->dma.flags.discard = FALSE; + sbuf->dma.flags.unsynchronized = FALSE; sbuf->dma.svga = NULL; sbuf->dma.boxes = NULL; + sbuf->dma.updates = NULL; - /* Decrement reference count */ - pipe_reference(&(sbuf->b.b.reference), NULL); - sbuf = NULL; + /* Decrement reference count (and potentially destroy) */ + dummy = &sbuf->b.b; + pipe_resource_reference(&dummy, NULL); } - /** * Note a dirty range. * * This function only notes the range down. It doesn't actually emit a DMA * upload command. That only happens when a context tries to refer to this - * buffer, and the DMA upload command is added to that context's command buffer. - * + * buffer, and the DMA upload command is added to that context's command + * buffer. + * * We try to lump as many contiguous DMA transfers together as possible. */ void @@ -309,7 +477,7 @@ svga_buffer_add_range(struct svga_buffer *sbuf, unsigned nearest_dist; assert(end > start); - + if (sbuf->map.num_ranges < SVGA_BUFFER_MAX_RANGES) { nearest_range = sbuf->map.num_ranges; nearest_dist = ~0; @@ -320,15 +488,9 @@ svga_buffer_add_range(struct svga_buffer *sbuf, /* * Try to grow one of the ranges. - * - * Note that it is not this function task to care about overlapping ranges, - * as the GMR was already given so it is too late to do anything. Situations - * where overlapping ranges may pose a problem should be detected via - * pipe_context::is_resource_referenced and the context that refers to the - * buffer should be flushed. */ - for(i = 0; i < sbuf->map.num_ranges; ++i) { + for (i = 0; i < sbuf->map.num_ranges; ++i) { int left_dist; int right_dist; int dist; @@ -340,6 +502,11 @@ svga_buffer_add_range(struct svga_buffer *sbuf, if (dist <= 0) { /* * Ranges are contiguous or overlapping -- extend this one and return. + * + * Note that it is not this function's task to prevent overlapping + * ranges, as the GMR was already given so it is too late to do + * anything. If the ranges overlap here it must surely be because + * PIPE_TRANSFER_UNSYNCHRONIZED was set. */ sbuf->map.ranges[i].start = MIN2(sbuf->map.ranges[i].start, start); @@ -363,8 +530,7 @@ svga_buffer_add_range(struct svga_buffer *sbuf, * pending DMA upload and start clean. */ - if(sbuf->dma.pending) - svga_buffer_upload_flush(sbuf->dma.svga, sbuf); + svga_buffer_upload_flush(sbuf->dma.svga, sbuf); assert(!sbuf->dma.pending); assert(!sbuf->dma.svga); @@ -398,47 +564,51 @@ svga_buffer_add_range(struct svga_buffer *sbuf, /** * Copy the contents of the malloc buffer to a hardware buffer. */ -static INLINE enum pipe_error -svga_buffer_update_hw(struct svga_screen *ss, struct svga_buffer *sbuf) +static enum pipe_error +svga_buffer_update_hw(struct svga_context *svga, struct svga_buffer *sbuf) { assert(!sbuf->user); - if(!sbuf->hwbuf) { + if (!svga_buffer_has_hw_storage(sbuf)) { + struct svga_screen *ss = svga_screen(sbuf->b.b.screen); enum pipe_error ret; + boolean retry; void *map; - + assert(sbuf->swbuf); - if(!sbuf->swbuf) + if (!sbuf->swbuf) return PIPE_ERROR; - - ret = svga_buffer_create_hw_storage(ss, sbuf); - if(ret != PIPE_OK) + + ret = svga_buffer_create_hw_storage(svga_screen(sbuf->b.b.screen), + sbuf); + if (ret != PIPE_OK) return ret; pipe_mutex_lock(ss->swc_mutex); - map = ss->sws->buffer_map(ss->sws, sbuf->hwbuf, PIPE_TRANSFER_WRITE); + map = svga_buffer_hw_storage_map(svga, sbuf, PIPE_TRANSFER_WRITE, &retry); assert(map); - if(!map) { + assert(!retry); + if (!map) { pipe_mutex_unlock(ss->swc_mutex); svga_buffer_destroy_hw_storage(ss, sbuf); return PIPE_ERROR; } memcpy(map, sbuf->swbuf, sbuf->b.b.width0); - ss->sws->buffer_unmap(ss->sws, sbuf->hwbuf); + svga_buffer_hw_storage_unmap(svga, sbuf); /* This user/malloc buffer is now indistinguishable from a gpu buffer */ assert(!sbuf->map.count); - if(!sbuf->map.count) { - if(sbuf->user) + if (!sbuf->map.count) { + if (sbuf->user) sbuf->user = FALSE; else align_free(sbuf->swbuf); sbuf->swbuf = NULL; } - + pipe_mutex_unlock(ss->swc_mutex); } - + return PIPE_OK; } @@ -447,8 +617,11 @@ svga_buffer_update_hw(struct svga_screen *ss, struct svga_buffer *sbuf) * Upload the buffer to the host in a piecewise fashion. * * Used when the buffer is too big to fit in the GMR aperture. + * This function should never get called in the guest-backed case + * since we always have a full-sized hardware storage backing the + * host surface. */ -static INLINE enum pipe_error +static enum pipe_error svga_buffer_upload_piecewise(struct svga_screen *ss, struct svga_context *svga, struct svga_buffer *sbuf) @@ -460,6 +633,7 @@ svga_buffer_upload_piecewise(struct svga_screen *ss, assert(sbuf->map.num_ranges); assert(!sbuf->dma.pending); + assert(!svga_have_gb_objects(svga)); SVGA_DBG(DEBUG_DMA, "dma to sid %p\n", sbuf->handle); @@ -476,12 +650,12 @@ svga_buffer_upload_piecewise(struct svga_screen *ss, if (offset + size > range->end) size = range->end - offset; - hwbuf = svga_winsys_buffer_create(ss, alignment, usage, size); + hwbuf = sws->buffer_create(sws, alignment, usage, size); while (!hwbuf) { size /= 2; if (!size) return PIPE_ERROR_OUT_OF_MEMORY; - hwbuf = svga_winsys_buffer_create(ss, alignment, usage, size); + hwbuf = sws->buffer_create(sws, alignment, usage, size); } SVGA_DBG(DEBUG_DMA, " bytes %u - %u\n", @@ -489,10 +663,10 @@ svga_buffer_upload_piecewise(struct svga_screen *ss, map = sws->buffer_map(sws, hwbuf, PIPE_TRANSFER_WRITE | - PIPE_TRANSFER_DISCARD); + PIPE_TRANSFER_DISCARD_RANGE); assert(map); if (map) { - memcpy(map, sbuf->swbuf, size); + memcpy(map, (const char *) sbuf->swbuf + offset, size); sws->buffer_unmap(sws, hwbuf); } @@ -500,7 +674,7 @@ svga_buffer_upload_piecewise(struct svga_screen *ss, hwbuf, sbuf->handle, SVGA3D_WRITE_HOST_VRAM, size, 0, offset, sbuf->dma.flags); - if(ret != PIPE_OK) { + if (ret != PIPE_OK) { svga_context_flush(svga, NULL); ret = SVGA3D_BufferDMA(svga->swc, hwbuf, sbuf->handle, @@ -523,10 +697,12 @@ svga_buffer_upload_piecewise(struct svga_screen *ss, } - - -/* Get (or create/upload) the winsys surface handle so that we can +/** + * Get (or create/upload) the winsys surface handle so that we can * refer to this buffer in fifo commands. + * This function will create the host surface, and in the GB case also the + * hardware storage. In the non-GB case, the hardware storage will be created + * if there are mapped ranges and the data is currently in a malloc'ed buffer. */ struct svga_winsys_surface * svga_buffer_handle(struct svga_context *svga, @@ -537,17 +713,21 @@ svga_buffer_handle(struct svga_context *svga, struct svga_buffer *sbuf; enum pipe_error ret; - if(!buf) + if (!buf) return NULL; sbuf = svga_buffer(buf); - - assert(!sbuf->map.count); + assert(!sbuf->user); - - if(!sbuf->handle) { - ret = svga_buffer_create_host_surface(ss, sbuf); - if(ret != PIPE_OK) + + if (!sbuf->handle) { + /* This call will set sbuf->handle */ + if (svga_have_gb_objects(svga)) { + ret = svga_buffer_update_hw(svga, sbuf); + } else { + ret = svga_buffer_create_host_surface(ss, sbuf); + } + if (ret != PIPE_OK) return NULL; } @@ -562,7 +742,7 @@ svga_buffer_handle(struct svga_context *svga, /* * Migrate the data from swbuf -> hwbuf if necessary. */ - ret = svga_buffer_update_hw(ss, sbuf); + ret = svga_buffer_update_hw(svga, sbuf); if (ret == PIPE_OK) { /* * Queue a dma command. @@ -625,10 +805,10 @@ svga_context_flush_buffers(struct svga_context *svga) assert(p_atomic_read(&sbuf->b.b.reference.count) != 0); assert(sbuf->dma.pending); - + svga_buffer_upload_flush(svga, sbuf); - curr = next; + curr = next; next = curr->next; } }